Answer:
SA = 85 ft²
Explanation:
To find the surface area of a 3-D shape, calculate the area of each face, then add them together. We are already given the area of each face.
One lateral face (triangle) is 15 ft².
The base (square) is 25 ft².
From the open pyramid, called a "net", we can see 5 faces in total: four triangles and one square.
Multiply the number of each shape by the area of the shape:
SA = (4 × 15 ft²) + (25 ft²)
SA = 60 ft² + 25 ft²
SA = 85 ft²