Question

pablo folds a straw into a triangle with side lengths of $4x^{2}-3$ inches, $4x^{2}-2$ inches, and $4x^{2}-1$ inches. which expression can be used to find the perimeter of the triangle, and what is the perimeter when $x = 1.5$?

1. $12x^{2}-6$; 21 inches
2. $12x^{2}$; 27 inches
3. $12x^{2}-6$; 30 inches
4. $12x^{2}$; 36 inches

Explanation:

Step1: Encontrar la expresión del perímetro

Sumamos los lados del triángulo: $(4x^{2}-3)+(4x^{2}-2)+(4x^{2}-1)=4x^{2}+4x^{2}+4x^{2}-3 - 2 - 1=12x^{2}-6$.

Step2: Sustituir $x = 1.5$

Sustituimos $x = 1.5$ en $12x^{2}-6$. Tenemos $12\times(1.5)^{2}-6=12\times2.25 - 6=27 - 6=21$ inches.

Answer:

A. $12x^{2}-6$; 21 inches