Question

the isosceles triangle has a perimeter of 7.5 m. which equation can be used to find the value of x if the shortest side, y, measures 2.1 m? 2x - 2.1 = 7.5 4.2 + y = 7.5 y - 4.2 = 7.5 2.1 + 2x = 7.5

Explanation:

Step1: Recall the perimeter formula for a triangle

The perimeter \( P \) of a triangle is \( P=\text{sum of all side lengths} \).
For an isosceles triangle with two sides of length \( x \) and one side of length \( y \), the perimeter formula is \( P = x + x+ y\).

Step2: Substitute the given values into the formula

We know that \( P = 7.5\) m and \( y = 2.1\) m.
Substituting these values into \( P=x + x + y\), we get \( 7.5=x + x+2.1\).
Since \( x + x=2x\), the equation becomes \( 2.1 + 2x=7.5\).

Answer:

\( 2.1 + 2x=7.5\) (the fourth option)