Question

A square pyramid has a base with side lengths each measuring 40 inches. The pyramid is 21 inches tall, with a slant height of 29 inches. What is the surface area of the pyramid? The base of a cylinder has a radius of 9 centimeters.

Answer 1

Answer:

3280 square inches

Step-by-step explanation:

The surface area of square pyramid = 4* the area of the triangular side + the area of the square base.

TRIANGULAR SIDE

The pyramid has an isosceles triangular side of size, a=40 inches, b= 29 inches, c = 29 inches.

Surface area = sqrt{ s(s-a)(s-b)(s-c) }

Where s= (a+b+c)/2

S= (40+29+29)/2 = 49

Surface area = sqrt{ 49(49-40)(49-29)(49-29)}

Surface area = 420 square inches

SQUARE BASE

Area of a square = a²

Area = 40² = 1600 square inches

Surface area of the pyramid = 4*420 + 1600 = 1680 + 1600

Surface area = 3280 square inches.

Answer 2

Answer:

3,920

Step-by-step explanation:

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