We know in order to get a area for a rectangle, it is length times the width, or height.
In this situation, we have the area with is 36cm^2 and 8cm. In order to find the with of the triangle, we must do the opposite than what'd we do to get the area. Since to get the area we multiply, in order to get a side we must divide.
36 / 8
= 4.5
This means that the width is 4.5, and the height is 8 (or length) with equal to 36cm^2
Hope this helped!
- Kat