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# Unit 4: Measurement and Geometry
## Angle Theorems
1. ```Transversal Parallel Line Theorems``` (TPT)
a. Alternate Angles are Equal ```(Z-Pattern)```
b. Corresponding Angles Equal ```(F-Pattern)```
c. Interior Angles add up to 180 ```(C-Pattern)```
- < img src = "https://dj1hlxw0wr920.cloudfront.net/userfiles/wyzfiles/58a52a99-05da-4595-88b8-2cbca91e8bbf.gif" width = "300" >
2. ```Supplementary Angle Triangle``` (SAT)
- When two angles add up to 180 degrees
- < img src = "https://embedwistia-a.akamaihd.net/deliveries/cdd1e2ebe803fc21144cfd933984eafe2c0fb935.jpg?image_crop_resized=960x600" width = "500" >
3. ```Opposite Angle Theorem (OAT)``` (OAT)
- Two lines intersect, two angles form opposite. They have equal measures
- < img src = "https://images.slideplayer.com/18/6174952/slides/slide_2.jpg" width = "400" >
4. ```Complementary Angle Theorem``` (CAT)
- The sum of two angles that add up to 90 degrees
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- < img src = "http://images.tutorvista.com/cms/images/67/complementary-angle.png" width = "300" >
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5. ```Angle Sum of a Triangle Theorem``` (ASTT)
- The sum of the three interior angles of any triangle is 180 degrees
- < img src = "https://dj1hlxw0wr920.cloudfront.net/userfiles/wyzfiles/f0516fa1-669b-441d-9f11-a33907a2a0b0.gif" width = "300" >
6. ```Exterior Angle Theorem``` (EAT)
- The measure of an exterior angle is equal to the sum of the measures of the opposite interior angles
-< img src = "https://www.katesmathlessons.com/uploads/1/6/1/0/1610286/exterior-angle-theorem-diagram-picture_orig.png" width = "300" >
7. ``` Isosceles Triangle Theorem``` (ITT)
- The base angles in any isosceles triangle are equal
- < img src = "http://www.assignmentpoint.com/wp-content/uploads/2016/06/isosceles-triangle-theorem.jpg" width = "400" >
8. ```Sum of The Interior Angle of a Polygon```
- The sum of the interioir angles of any polygon is ```180(n-2)``` or ```180n - 360```, where ```n``` is the number of sides of the polygon
- < img src = "https://i.ytimg.com/vi/tmRpwCM1K1o/maxresdefault.jpg" width = "500" >
9. ```Exterior Angles of a Convex Polygon```
- The sum of the exterior angle of any convex polygon is always ```360 degrees```
- < img src = "https://image.slidesharecdn.com/findanglemeasuresinapolygon-110307143453-phpapp02/95/find-angle-measures-in-a-polygon-11-728.jpg?cb=1299508555" width = "400" >
## Properties of Quadrilaterals
- Determine the shape using the properties of it
|Figure|Properties|
|:-----|:---------|
|Scalene Triangle|no sides equal|Length of line segment|
|Isosceles Triangle| two sides equal|Length of line segment|
|Equilateral Triangle|All sides equal|Length of line segment|
|Right Angle Triangle|Two sides are perpendicular to each other|
|Parallelogram|Opposite sides are parallel and have equal length. Additionally, the diagonals bisect each other|
|Rectangle|Adjacent sides are perpendicular to each other. Furthermore, the diagonals bisect each other and are equal in length|
|Square|All sides are equal in length. The adjacent sides and diagonals are perpendicular. The adjacent sides are equal in length, so as the diagonals|
|Rhombus|Opposite sides are parallel and all sides are equal to each other, the diagonals are perpendicular|
|Trapezoid|There is one pair of opposite sides and they are parallel and unequal in length|
|Kite|The diagonals are perpendicular|
## 2D Geometry Equations
|Shape|Formula|Picture|
|:----|:------|:------|
|Rectangle|```Area```: $`lw`$ < br > ```Perimeter```: $`2(l+w)`$|< img src = "https://lh5.googleusercontent.com/Ib1Evz5PUwd4PzRmFkHj9IY2Is-UthHoUyyiEHAzkJP-296jZvMmHJM1Kws4PmuTeYHV2ZBIJenc4W1pKtsSHvU82lyjOed2XKBb1PWnoaeJ3sSPuaJgSTg8JWbxrvplabCanvTD" width = "200" > |
|Triangle|```Area```: $`\frac{bh}{2}`$ < br > ```Perimeter```: $`a+b+c`$|< img src = "https://lh6.googleusercontent.com/covvHwXxQhrK2Hr0YZoivPkHodgstVUpAQcjpg8sIKU25iquSHrRd2EJT64iWLsg_75WnBw4T9P0OTBiZDkpqEkXxflZQrL16sNhcFfet_z4Mw5EPFgdx_4HzsagV0Sm5jN6EKr_" width = "200" > |
|Circle|```Area```: $`πr^2`$ < br > ```Circumference```: $`2πr`$ or $`πd`$|< img src = "https://lh5.googleusercontent.com/RydffLVrOKuXPDXO0WGPpb93R8Ucm27qaQXuxNy_fdEcLmuGZH4eYc1ILNmLEx8_EYrRuOuxFavtL9DF1lTWYOx9WaYauVlu0o_UR6eZLeGewGjFNUQSK8ie4eTm1BMHfRoQWHob" width = "200" > |
|Trapezoid|```Area```: $` \frac{(a+b)h}{2}`$ < br > ```Perimeter```: $`a+b+c+d`$|< img src = "https://lh6.googleusercontent.com/_nceVtFlScBbup6-sPMulUTV3MMKu1nonei0D1WY-KRkpHSbPCIWgDO8UGDQBGKh8i0dkAqOhFUHl7YHCFOt6AMRSJiXALlBBY0mBo1MMZxHRVcg8DknSlv4ng7_QswcZtaRwrJb" width = "200" > |
## 3D Geometry Equations
|3D Object|Formula|Picture|
|:----|:------|:------|
|Rectangular Prism|```Volume```: $`lwh`$ < br > ```SA```: $`2(lw+lh+wh)`$|< img src = "https://lh6.googleusercontent.com/-mqEJ4AMk3xDPfqH5kdVukhtCGl3fgTy2ojyAArla54c7UoAnqKW_bsYSaFySXLplE59pqLIg5ANZAL1f6UEejsrKJwQCfyO7gwUQmSDoJJtQG_WkfHcOFDjidXV4Y4jfU2iA5b-" width = "200" > |
|Square Based Pyramid|```Volume```: $`\frac{1}{3} b^2 h`$ < br > ```SA```: $`2bs+b^2`$|< img src = "https://lh5.googleusercontent.com/iqaaJtx-Kx4vFT3Yp6YLOmpDFL7_qk2uh0Z21pgPJMDRgchiUBcHeTWkMrR9mFjxCj8w7za1xwN9bo4UFACPZRMSl-V67uPv9FvDyNJVjedmeehx5K-iUK9sBhObhNsLJpNItkg0" width = "200" > |
|Sphere|```Volume```: $`\frac{4}{3} πr^3`$ < br > ```SA```: $`4πr^2`$|< img src = "https://lh6.googleusercontent.com/DL6ViJLbap2dcSAlZnYKR7c33033g8WuJVvqz0KpzCyIJ0wXyrh5ejoLhrTxlX9uASQlxPmihm8doU1sNbaQxqBcTaPnP-lC6LUrPqzPNi11AHiHQAu3ag7uIGcwzkdC9e5uo1en" width = "200" > |
|Cone|```Volume```: $` \frac{1}{3} πr^2 h`$ < br > ```SA```: $`πrs+πr^2`$|< img src = "https://lh5.googleusercontent.com/V3iZzX8ARcipdJiPPFYso_il3v_tcrYHZlFnq3qkekRSVBVcj8OzWxMuBqN45aHbv6y-fDH4uY11Gus3KMrvf_Z_TvsfJCwZZ19Ezf7Yj6DzVirp-Gx3V0Qy793ooUwTDmdKW_xq" width = "200" > |
|Cylinder|```Volume```: $`πr^2h`$ < br > ```SA```: $`2πr^2+2πh`$|< img src = "https://lh5.googleusercontent.com/4uWukD3oNUYBG-fLX2-g58X8at0h74al7BJI5l78LZ0Bu9nXuZnt9dp9xiETeLTqykP-WWFdO_H5by4RkgDVxSENZgootSrAsOUoY2RWubflNOAau1bVFgm9YIe59SmiFlyxwgDV" width = "200" > |
|Triangular Prism|```Volume```: $`ah+bh+ch+bl`$ < br > ```SA```: $` \frac{1}{2} blh`$|< img src = "https://lh3.googleusercontent.com/_oRUVgfdksfUXGKQk3AtrtY70E8jEq-RRK-lB9yKc_Rtio2f2utGAY-rI4UqjWEeTzUoN_r7EiqdZZeeE12EY-fiV55QQKdvnv4y4VaxQ9xt9Izugp6Ox_LqIUpQzPKVldptgKWm" width = "200" > |
## Optimization (For Maximimizing Area/Volume, or Minimizing Perimeter/Surface Area)
### 2D Objects
|Shape|Maximum Area|Minimum Perimeter|
|:----|:-----------|:----------------|
|4-sided rectangle|A rectangle must be a square to maximaze the area for a given perimeter. The length is equal to the width< br > $`A = lw`$< br > $`A_{max} = (w)(w)`$< br > $`A_{max} = w^2`$|A rectangle must be a square to minimaze the perimeter for a given area. The length is equal to the width.< br > $`P = 2(l+w)`$< br > $`P_{min} = 2(w + w)`$< br > $`P_{min} = 2(2w)`$< br > $`P_{min} = 4w`$|
|3-sided rectangle|$`l = 2w`$< br > $`A = lw`$< br > $`A_{max} = 2w(w)`$< br > $`A_{max} = 2w^2`$|$`l = 2w`$< br > $`P = l+2w`$< br > $`P_{min} = 2w+2w`$< br > $`P_{min} = 4w`$|
### 3D Objects
|3D Object|Maximum Volumne|Minimum Surface Area|
|:--------|:--------------|:-------------------|
|Cylinder(closed-top)|The cylinder must be similar to a cube where $`h = 2r`$< br > $`V = πr^2h`$< br > $`V_{max} = πr^2(2r)`$< br > $`V_{max} = 2πr^3`$|The cylinder must be similar to a cube where $`h = 2r`$< br > $`SA = 2πr^2+2πrh`$< br > $`SA_{min} = 2πr^2+2πr(2r)`$< br > $`SA_{min} = 2πr^2+4πr^2`$< br > $`SA_{min} = 6πr^2`$|
|Rectangular Prism(closed-top)|The prism must be a cube, < br > where $`l = w = h`$< br > $`V = lwh`$< br > $`V_{max} = (w)(w)(w)`$< br > $`V_{max} = w^3`$|The prism must be a cube, < br > where $`l = w = h`$< br > $`SA = 2lh+2lw+2wh`$< br > $`SA_{min} = 2w^2+2w^2+2w^2`$< br > $`SA_{min} = 6w^2`$|
|Cylinder(open-top)|$`h = r`$< br > $`V = πr^2h`$< br > $`V_{max} = πr^2(r)`$< br > $`V_{max} = πr^3`$|$`h = r`$< br > $`SA = πr^2+2πrh`$< br > $`SA_{min} = πr^2+2πr(r)`$< br > $`SA_{min} = πr^2+2πr^2`$< br > $`SA_{min} = 3πr^2`$|
|Square-Based Rectangular Prism(open-top)|$`h = \frac{w}{2}`$< br > $`V = lwh`$< br > $`V_{max} = (w)(w)(\frac{w}{2})`$< br > $`V_{max} = \frac{w^3}{2}`$|$`h = \frac{w}{2}`$< br > $`SA = w^2+4wh`$< br > $`SA_{min} = w^2+4w(\frac{w}{2})`$< br > $`SA_{min} = w^2+2w^2`$< br > $`SA_{min} = 3w^2`$|
## Labelling
- Given any polygons, labelling the vertices must always:
1. use ```CAPITAL LETTERS```
2. they have to be labeled in ```clockwise``` or ```counter-clockwise``` directions
- For a triangle, the side lengths are labeled in ```LOWERCASE LETTERS``` associated to the opposite side of the vertex
- < img src = "http://www.technologyuk.net/mathematics/trigonometry/images/trigonometry_0073.gif" width = "400" >
## Median
- Each median divides the triangle into 2 smaller triangles of equal area
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- The centroid is exactly $`\dfrac{2}{3}`$the way of each median from the vertex, or $`\dfrac{1}{3}`$ the way from the midpoint of the opposite side, or ```2:1``` ratio
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- The three medians divide the triangle into ```6``` smaller triangles of equal area and ```3 pairs``` of congruent triangles
- < img src = "https://blog.udemy.com/wp-content/uploads/2014/05/d-median.png" width = "500" >
## Terms:
- ```Altitude``` The height of a triangle, a line segment through a vertex and perpendicular to the opposite side
- ```Orthocenter```: where all 3 altitudes of the triangle intersect
- < img src = "https://mathbitsnotebook.com/Geometry/Constructions/orthocenter1a.jpg" width = "300" >
- ```Midpoint```: A point on a line where the length of either side of the point are equal
- ```Median```: A line segment joining the vertex to the midpoint of the opposite side
- ```Midsegment```: A line joining 2 midpoints of the 2 sides of a triangle
- ```Centroid```: The intersection of the 3 medians of a triangle
- < img src = "http://www.mathwords.com/c/c_assets/centroid.jpg" width = "300" >
## Proportionality theorem:
- The midsegment of a triangle is ```half``` the length of the opposite side and ```parallel``` to the opposite side
- Three midsegment of a triangle divide ```4 congruent``` triangles with the same area
- The Ratio of the outer triangle to the triangle created by the 3 midsegments is ```4 to 1```
- < img src = "https://encrypted-tbn0.gstatic.com/images?q=tbn:ANd9GcSPYlT2JwH4oMYHmpq0DLhBTi1goY0JaRBpNdmZBWgWKSaXAJTM" width = "300" >
## Tips
- Make sure to know your optimization formualas
- Read the word problems carefully, determine which formual to use
- Never **ASSUME** , be sure to **CALCULATE** as most of the time the drawings are **NOT ACCURATE**
- To find ```missing area```, take what you have, subtract what you don't want
- Don't be afraid to draw lines to help you solve the problem