1

Problem

The perimeter of an isosceles triangle is 15 units. Find out the length of the third side of the triangle if the equal sides measure 4 units each.

2

Step

Given that perimeter of the isosceles triangle (P) & length of equal sides are

15 units and 4 units

3

Formula

The perimeter of the Isosceles triangle is Perimeter = 2 \$\times\$ (length of equal side) + length of the third side.

4

Step

Substitute the values into the formula:

P = \$15 = (2 \times 4) + c\$

5

Step

Now, solve for c:

15 = 8 - c

c = 15 - 8

c = 7 units

6

Solution

The length of the third side of the isosceles triangle is 7 units.

7

Sumup

Please summarize steps

Choices

8

Choice-A

If x = 1, the total perimeter would be 4 + 4+1 = 9, which is incorrect

Wrong 1 unit

9

Choice-B

This is incorrect because it does not satisfy the perimeter equation 2a + c = 15

Wrong 12 units

10

Choice-C

If x = 10, the total perimeter would be 4 + 4 + 10 = 18, which is incorrect

Wrong 10 units

11

Choice-D

It is correct because it satisfies the given perimeter condition

Correct 7 units

12

Answer

Option

D

13

Sumup

Please summarize choices