Question

The perimeter of an isosceles triangle is 30 cm. The length of each congruent side is 3cm more than the length of its base. Find the lengths of all the sides.

Answer 1

Given:

the perimeter of an isosceles triangle 30cm

The length of each congruent side is 3cm more than the length of its base.

Let the length of the base side = x

So, the length of each congruent side = x + 3

the perimeter is the sum of the lengths of the sides of the triangle

So,

$(x+3)+(x+3)+x=30$

Solve the equation to find the value of x

$\begin{gathered} x+3+x+3+x=30 \\ 3x+6=30 \\ 3x=30-6 \\ 3x=24 \\ \\ x=\frac{24}{3}=8 \end{gathered}$

So, the length of the base side = 8 cm

And the length of each congruent side = 8 + 3 = 11 cm

So,

The lengths of all sides are: 11 cm, 11 cm and 8 cm