A contractor is building a pool labeled ABCD on the plans. If [tex]\( AC = 15y - 7 \)[/tex] and [tex]\( BD = 2y + 6 \)[/tex], what value of [tex]\( y \)[/tex] ensures the pool is a rectangle?

A. [tex]\(-13\)[/tex]
B. [tex]\(-1\)[/tex]
C. [tex]\(1\)[/tex]
D. [tex]\(13\)[/tex]



Answer :

To determine the value of [tex]\( y \)[/tex] that ensures the pool labeled ABCD is a rectangle, we need to analyze the properties of a rectangle. One key property of a rectangle is that its diagonals are equal in length. Therefore, we need to set the lengths of the diagonals [tex]\( AC \)[/tex] and [tex]\( BD \)[/tex] equal to each other and solve for [tex]\( y \)[/tex].

Here are the equations for the diagonals given in the problem:
[tex]\[ AC = 15y - 7 \][/tex]
[tex]\[ BD = 2y + 6 \][/tex]

Since for a rectangle, the diagonals [tex]\( AC \)[/tex] and [tex]\( BD \)[/tex] must be equal, we set these two expressions equal to each other:
[tex]\[ 15y - 7 = 2y + 6 \][/tex]

To solve for [tex]\( y \)[/tex], we follow these steps:

1. Isolate the variable [tex]\( y \)[/tex] on one side of the equation. First, subtract [tex]\( 2y \)[/tex] from both sides:
[tex]\[ 15y - 2y - 7 = 6 \][/tex]

2. Simplify the equation:
[tex]\[ 13y - 7 = 6 \][/tex]

3. Add 7 to both sides to move the constant term away from the [tex]\( y \)[/tex] term:
[tex]\[ 13y = 13 \][/tex]

4. Divide both sides by 13 to solve for [tex]\( y \)[/tex]:
[tex]\[ y = \frac{13}{13} \][/tex]
[tex]\[ y = 1 \][/tex]

Therefore, the value of [tex]\( y \)[/tex] that ensures the pool is a rectangle is [tex]\( 1 \)[/tex].

The correct answer is:
[tex]\[ 1 \][/tex]