Question

Pablo folds a straw into a triangle with side lengths of 4x2−3 inches, 4x2−2 inches, and 4x2−1 inches. Which expression can be used to find the perimeter of the triangle, and what is the perimeter when x = 1.5?

12x2 −6; 21 inches
12x2; 27 inches
12x2 −6; 30 inches
12x2; 36 inches

Answer 1

Perimeter = (4x^2 − 3) + (4x^2 − 2) + (4x^2 − 1) = 12x^2 − 6.

For x = 1.5: x^2 = 2.25, so perimeter = 12(2.25) − 6 = 27 − 6 = 21 inches.

So: 12x^2 − 6; 21 inches.