If x = 5 cm, y = 12 cm, and z = 13 cm, what is the surface area of the geometric shape formed by this net?

a. 82 sq. cm
b. 270 sq. cm
c. 210 sq. cm
d. 320 sq. cm

the answer is C.  210 sq. cm

Step-by-step explanation:

Find the area of the triangle

The area of one of the triangular faces can be found by using the formula below.  

a = 1/2 bh

a = 1/2 (5 cm) (12 cm)

a = 30 sq. cm

Since there are two triangular faces, multiply the area of one triangular face by 2. The area of two triangular faces is 60 cm2.

Next, find the area of each of the three rectangular faces using the formula, area = lw.

1st rectangle

a = lw

a =  (5 cm) (5 cm)

a = 25 sq. cm

2nd rectangle

a = lw

a = (5 cm) (12 cm)

a = 60 sq. cm

3rd rectangle

a = lw

a = (5 cm) (13 cm)

a - 65 sq. cm

Add the three rectangle areas to find a total of 150 sq. cm.

To find the surface area of the triangular prism, add the area of the two triangular faces to the area of the three rectangular faces.

60 sq. cm + 150 sq. cm = 210 sq. cm

the correct answer is the second option