ACT Math : How to find the height of of an acute / obtuse isosceles triangle

Study concepts, example questions & explanations for ACT Math

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Example Questions

Example Question #1 : Triangles

An isosceles triangle has a base of 12\ cm and an area of 42\ cm^{2}. What must be the height of this triangle?

Possible Answers:

7\ cm

8\ cm

6\ cm

10\ cm

9\ cm

Correct answer:

7\ cm

Explanation:

A=\frac{1}{2}bh

6x=42

x=7

Example Question #171 : Triangles

What is the height of an isosceles triangle which has a base of  and an area of ?

Possible Answers:

Correct answer:

Explanation:

The area of a triangle is given by the equation: 

In this case, we are given the area () and the base () and are asked to solve for height ().

To do this, we must plug in the given values for  and which gives the following:

We then must multiply the right side, and then divide the entire equation by 2, in order to solve for :

Therefore, the height of the triangle is .

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