Question

What is the surface area of a pyramid if its one triangular face has an area of 20 sq. cm and its square base has a side of 5cm?A. 100 sq.cmB. 105 sq.cmC. 110 sq. cmD. 115 sq.cm

Answer 1

To solve this problem, we will use the following formula for the surface area of a square pyramid:

$SA=BA+4A_t,$

where BA= base area, and A_t is the area of one of the lateral triangles.

Now, we are given that:

$A_t=20cm^2.$

Recall that the area of a square is given by the following formula:

$A_s=side^2.$

We are given that the side of the base is 5 cm long, therefore, the base area is:

$A_s=(5cm)^2=25cm^2.$

Finally, we get that:

$SA=25cm^2+4(20cm^2)=105cm^2.$

Answer:

$105cm^2.$