Alison needs to buy a canvas tarp sized B) 105 ft².
Step-by-step explanation:
Step 1; The square pyramid has a square base with side length 5 feet. There are 4 triangles with base lengths of 5 feet and heights of 8 feet. To calculate the area of the entire canvas tarp we add the areas of the square and the area of the 4 triangles.
Step 2; The area of a square is the square of the side length. The side length is 5 feet.
Area of the square = side length × side length = 5 × 5 = 25 ft².
The area of any triangle is half the product of the base and height.
Area of 1 triangle = [tex]\frac{1}{2}[/tex] × base × height =  20 ft².
Area of 4 triangles = 4 × Area of 1 triangle = 4 × 20 = 80 ft².
Area of entire shape = Area of square + Area of triangles = 25 + 80 = 105 ft².
So Alison needs 105 ft² of canvas tarp.
