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

The equation can be used to find the value of x is 2.1 + 2x = 7.5 ⇒ D

Step-by-step explanation:

* Lets talk about the isosceles triangle

- The isosceles triangle has two equal sides

- The angle between the two equal sides is called the vertex angle

- The side opposite to the vertex angle is called the base of the triangle

- The end vertices of the base are called the base angles  

- The two base angles are equal in measure

- The perimeter of any triangle is the sum of the length of its  

 three sides

* Lets solve the problem

∵ The triangle is isosceles triangle

- The shortest side is opposite to the shortest angle  

∵ The two base angles are equal in measure

∴ The shortest angle is the vertex angle which opposite to the  

  base of the triangle

∴ The shortest side is the base of the triangle

∵ The length of the shortest side is y

∴ The length of the equal sides is x

∴ The lengths of the sides of the triangles are x , x , y

- The perimeter of the triangle is the sum of the length of its  

  three sides

∴ The perimeter of the triangle = x + x + y

∵ The perimeter of the triangle is 7.5 m

∴ x + x + y = 7.5 ⇒ add the like terms

∴ 2x + y = 7.5

∵ y = 2.1 ⇒ given

∴ 2x + 2.1 = 7.5

∴ 2.1 + 2x = 7.5

* The equation can be used to find the value of x is 2.1 + 2x = 7.5