College

The isosceles triangle has a perimeter of 7.5 m. Which equation can be used to find the value of [tex]x[/tex] if the shortest side, [tex]y[/tex], measures 2.1 m?

A. [tex]2x - 2.1 = 7.5[/tex]
B. [tex]4.2 + y = 7.5[/tex]
C. [tex]y - 4.2 = 7.5[/tex]
D. [tex]2.1 + 2x = 7.5[/tex]

Answer :

To solve the problem regarding the isosceles triangle's perimeter, let's break it down step-by-step:

1. Understanding the Problem:
- We have an isosceles triangle, which means two of its sides are of equal length.
- The perimeter of the triangle is given as 7.5 meters.
- The shortest side is given as 2.1 meters. We'll label this side as [tex]\( y = 2.1 \)[/tex] meters.

2. Identifying the Unknowns:
- Let the length of each of the equal sides be [tex]\( x \)[/tex].

3. Setting Up the Equation:
- The formula for the perimeter of a triangle is the sum of the lengths of its three sides.
- For an isosceles triangle with two equal sides, the equation can be written as:
[tex]\[
x + x + y = \text{Perimeter}
\][/tex]

4. Plugging in the Given Values:
- We know:
- [tex]\( y = 2.1 \)[/tex] meters
- Perimeter = 7.5 meters
- Substitute these values into the equation:
[tex]\[
x + x + 2.1 = 7.5
\][/tex]
- This simplifies to:
[tex]\[
2x + 2.1 = 7.5
\][/tex]

5. Finding the Equation:
- The equation [tex]\( 2x + 2.1 = 7.5 \)[/tex] represents the relationship that will allow us to solve for [tex]\( x \)[/tex].

So, the correct equation that can be used to find the value of [tex]\( x \)[/tex] is:
[tex]\[ 2.1 + 2x = 7.5 \][/tex]