Lesson Example Discussion Quiz: Class Homework |
Step-1 |
Title: Orthocentre |
Grade: 7-a Lesson: S3-L7 |
Explanation: |
Step | Type | Explanation | Answer |
---|---|---|---|
1 |
Problem |
Find the co-ordinates of the mid point of the line segment joining the points A(–3,2) and B(7,8).
|
|
2 |
Given |
A triangle whose vertices are the points A(1,–2), B(3,1) and C(–2,3). |
|
3 |
Step |
If AD is drawn perpendicular to BC then its slope is \$5/2\$. |
\begin{align} && y + 2 &= \frac{5}{2} (x – 1) \\ \Rightarrow && 5x – 2y &= 9 \tag{1} \\ \end{align} |
4 |
Step |
Solving equation (1) and (2). The orthocentre is the point of intersection of altitudes AD and BE. |
\begin{align} 15x – 6y = 27& \\ \underline{+15x – 25y = 20}& \\ 19y = 7& \\ \\ y = \frac{7}{19} \\ \end{align} |
5 |
Step |
Substitute \$ y = \frac{7}{19}\$ in (1), we get |
\begin{align} \require{cancel} 5x - 2(\frac{7}{19} ) &= 9 \\ x &= \frac{37}{19} \\ \end{align} |
6 |
Step |
Answer |
The ortho centre is \$( \frac{37}{19}, \frac{7}{19})\$. |
Copyright © 2020-2022 saibook.us Contact: info@saibook.us Version: 1.5 Built: 27-March-2023 9:00 PM EST