Answer:
The surface area of the pyramid is 340.2 cm²
Explanation:
We can find the surface area of this pyramid by adding up the area of its square base and the four side triangles.
We're told that the base has a side length of 9.0 cm, so we know that its area is (9.0cm)², or 81cm²
We are told that the height of the side triangles is 14.4 cm. To find the area of a triangle, simply multiply its width times its height, and divide by two:
(14.4cm × 9cm) ÷ 2
= 129.6cm² ÷ 2
= 64.8 cm²
Now we can multiply that by 4, and add it to the base area to get the total surface area of the pyramid:
4 × 64.8cm² + 81cm²
= 259.2cm² + 81cm²
= 340.2cm²