Answer:
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
