The area of a triangle is 36 cm2 and its height is 9 cm. Calculate the length of its base. Also, calculate the height of a triangle with an area of 180 cm2 and a base of 20 cm. Finally, calculate the

Area $= 36 \text{ cm}^2$
Height $= 9 \text{ cm}$

To find the base, multiply both sides by $\frac{2}{9}$:

The base of the triangle is $\boxed{\text{8 cm}}$.

2)

Area $= 180 \text{ cm}^2$
Base $= 20 \text{ cm}$

To find the height, divide both sides by 10:

The height of the triangle is $\boxed{\text{18 cm}}$.

3)

Area $= 67.2 \text{ cm}^2$
Height $= 16 \text{ cm}$

To find the base, divide both sides by 8:

The base of the triangle is $\boxed{\text{8.4 cm}}$.