Question

A triangle-shaped machine part has sides of 21/2 inches, 31/4 inches, and 5 inches. The triangle's perimeter is

A. 103/4 inches.
B. 111/2 inches.
C. 113/8 inches.
D. 101/8 inches.

Answer 1

add them, make botom number same (make them 4)

21/2 times 2/2=42/4
31/4=31/4
5/1 times 4/4=20/4

add
42/4+31/4+20/4=(42+31+20)/4=93/4

what is wrong with this system, the right answer is not there