Question

Paolo was asked to find the original dimension of an enlarged pentagon. His solution is shown next to the pentagons. A small pentagon has a bottom side length of x centimeters and left side length of 3 centimeters. A larger pentagon has a bottom side length of 8 centimeters and left side length of 12 centimeters. Write a proportion. StartFraction 3 over 12 EndFraction = StartFraction x over 8 EndFraction Cross multiply. 8 x = 36 Solve for x. x = 4.5 Not drawn to scale What error did Paolo make in his solution? Paolo set up an incorrect proportion. Paolo made an error when he cross multiplied the proportion. Paolo divided incorrectly when he solved for x. Paolo multiplied instead of divided when he solved for x.

Answer 1

Answer:

  Paolo made an error when he cross multiplied the proportion

Step-by-step explanation:

The proportion is ...

  $\dfrac{3}{12}=\dfrac{x}{8}$

"Cross multiply" means "multiply both sides of the equation by the product of the denominators."

  $\dfrac{3}{12}(12)(8)=\dfrac{x}{8}(12)(8) \quad\text{cross multiply}\\\\(3)(8)=(x)(12) \quad\text{Paolo got something different}$

Answer 2

Answer:

 Paolo made an error when he cross multiplied the proportion

ed 2020