Answer:
The pyramid's surface area is 78 square centimeters
Step-by-step explanation:
The formula of the surface area of a pyramid is S.A = A + [tex]\frac{1}{2}[/tex] p s, where
- A is the area of its base
- p is the perimeter of its base
- s is the slant height of it
∵ The area of the base of a triangular pyramid is 28 cm²
∴ A = 28 cm²
∵ The perimeter of the base is 20 cm
∴ p = 20 cm
∵ The he slant height is 5 cm
∴ s = 5 cm
- Substitute these values in the formula of the surface area
above to find it
∵ S.A = 28 + [tex]\frac{1}{2}[/tex] (20)(5)
∴ S.A = 28 + 50
∴ S.A = 78 cm²
The pyramid's surface area is 78 square centimeters
