Year 10
Higher
Use trigonometry to find the perpendicular height of a triangle
Year 10
Higher
Use trigonometry to find the perpendicular height of a triangle
Link copied to clipboard
These resources will be removed by end of Summer Term 2025.
Switch to our new teaching resources now - designed by teachers and leading subject experts, and tested in classrooms.
These resources were created for remote use during the pandemic and are not designed for classroom teaching.
Lesson details
Key learning points
- In this lesson, we will identify the perpendicular height of triangles, use trigonometry to find the perpendicular height and apply this to find the area of a triangle.
Licence
This content is made available by Oak National Academy Limited and its partners and licensed under Oak’s terms & conditions (Collection 1), except where otherwise stated.
3 Questions
Q1.
A ladder leans against a wall. It is 3m away from the wall at an angle of 60 degrees. What is the length of the ladder?

x = 1.5 m
x = 4.70 m
Q2.
2. A man stands exactly 8m from a lamppost. He looks to the top of the lamppost, as shown. What is the height of the lamppost? Answer to 1 dp

11.9 m
13.4 m
5.4 m
Q3.
Find the perpendicular height of this parallelogram ( to 1 dp)

10 cm
3.5 cm
3.54 cm
3 Questions
Q1.
If b is the base, identify the perpendicular height of this triangle.

s
u
Q2.
Find the perpendicular height of the triangle.

0.0333… cm
1 cm
Q3.
Find the perpendicular height of the triangle. Give your answer to one decimal place.

5.9 cm
8 cm