The area of square base = 324 m²

The length of the square side = √324 = 18

The side of the square is equal to the base of the triangle.

The formula of area of triangle = (1/2)*base* height

Calculations

⇒135 = (1/2)*18* h

⇒ 135 = 9h

⇒ 135/9 = h

⇒ 15 = h

⇒ height = 15 m

To get the height of the Pyramid, the height of the Triangle and half the length of the side of the square form a right angled triangle.

Hypotenus = 15

Half length of square = 18/2 = 9

Height of Pyramid = H

To solve this problem we have to use the Pythagorean theorem. The longest side of the triangle is called the "hypotenuse". C² is the longest side so it is the hypotenuse . To calculate h² we have to do c² - β² = h².

15² = H² + 9²

225 =H² + 81

H² + 81 = 225

H² = 225 - 81

H² = 144 **Take the square root of both sides**

H = √144

H = 12

**Height = 12 meters. **

**Option C.**