diff --git a/Grade 10/Math/MPM2DZ/Math Oral Presentation Questions/Analytical Geometry.md b/Grade 10/Math/MPM2DZ/Math Oral Presentation Questions/Analytical Geometry.md index 6aecda9..b210c3e 100644 --- a/Grade 10/Math/MPM2DZ/Math Oral Presentation Questions/Analytical Geometry.md +++ b/Grade 10/Math/MPM2DZ/Math Oral Presentation Questions/Analytical Geometry.md @@ -4,10 +4,73 @@ Lets first find each of the side lengths to determine if the triangle is **obtuse**, **acute** or scalene. -$`AB = \sqrt{(-1-7)^2 + (5-2)^2} = \sqrt{64 + 9} = \sqrt{73}`$ +$`\overline{AB} = \sqrt{(-1-7)^2 + (5-2)^2} = \sqrt{64 + 9} = \sqrt{73}`$ -$`BC = \sqrt{(7-(-1))^2 + (2-(-4))^2} = \sqrt{64 + 36} = \sqrt{100} = 10`$ +$`\overline{BC} = \sqrt{(7-(-1))^2 + (2-(-4))^2} = \sqrt{64 + 36} = \sqrt{100} = 10`$ -$`AC = \sqrt{(-1-(-1))^2 + (5-(-4))^2} = \sqrt{0^2 + 9^2} = \sqrt{81} = 9`$ +$`\overline{AC} = \sqrt{(-1-(-1))^2 + (5-(-4))^2} = \sqrt{0^2 + 9^2} = \sqrt{81} = 9`$ -$`\since \ No newline at end of file +$`\because \overline{AB} =\not \overline{BC} =\not \overline{AC}`$ + +$`\therefore \triangle ABC`$ is a scalene triangle. + +### Question 1 b) + +The `orthocenter` is the POI of the heights of a triangle. + +$`m_{AB} = \dfrac{2-5}{7-(-1)} = \dfrac{-3}{8}`$ + +$`m_{\perp AB} = \dfrac{8}{3}`$ + +$`y_{\perp AB} - (-4) = \dfrac{8}{3}(x - (-1)) \implies y_{perp AB} + 4 = \dfrac{8}{3}(x+1)`$ + +$`y_{\perp AB} = \dfrac{8}{3}x + \dfrac{8}{3} - 4`$ + +$` y_{\perp AB} = \dfrac{8}{3}x - \dfrac{4}{3} \quad (1)`$ + +$`m_{BC} = \dfrac{2-(-4)}{7-(-1)} = \dfrac{6}{8} = \dfrac{3}{4}`$ + +$`m_{\perp BC} = \dfrac{-4}{3}`$ + +$`y_{\perp BC} - 5 = \dfrac{-4}{3}(x-(-1)) \implies y_{\perp BC} - 5 = \dfrac{-4}{3}(x+1)`$ + +$`y_{\perp BC} = \dfrac{-4}{3}x - \dfrac{4}{3} + 5`$ + +$`y_{\perp BC} = \dfrac{-4}{3}x + \dfrac{11}{3}`$ + +```math + +\begin{cases} + +y_{\perp AB} = \dfrac{8}{3}x - \dfrac{4}{3} & \text{(1)} \\ + +\\ +y_{\perp BC} = \dfrac{-4}{3}x + \dfrac{11}{3} & \text{(2)} \\ +\end{cases} +``` + +Sub $`(1)`$ into $`(2)`$: + +$`\dfrac{8}{3}x - \dfrac{4}{3} = \dfrac{-4}{3} + \dfrac{11}{3}`$ + +$`8x - 4 = -4x + 11`$ + +$`12x = 15`$ + +$`x = \dfrac{5}{4} \quad (3)`$ + +Sub $`(3)`$ into $`(2)`$ + +$`y = \dfrac{-20}{12} + \dfrac{11}{3}`$ + +$`y = \dfrac{-5}{3} + \dfrac{11}{3}`$ + +$`y = \dfrac{6}{3} = 2`$ + +$`y = 2`$ + +$`\therefore`$ The `orthocenter` is at $`(\dfrac{5}{4}, 2)`$ + +### Question 2 a) + +midpoint = $`\large (\dfrac{\sqrt{72} + \sqrt{32}}{2}, \dfrac{-\sqrt{12} - \sqrt{48}}{2} \large )`$