Question

the perimeter of an isosceles triangle is 50 cm if its unequal side measures 20 cm find the length of equal side ​

Answer 1

Given:

• perimeter of the isosceles triangle = 50cm
• measure of unequal side of the triangle = 20cm

${\sf{\underline{\underline{\orange{To\:Find}}}}}$

length of the equal side of the triangle

${\sf{\underline{\underline{\pink{Solution}}}}}$

let "x" be the other two equal sides of the isosceles triangle

${\sf{\underline{\underline{\color{green}{therefore}}}}}$

$\sf{x + x + 20 = 50cm}$

$\implies\sf{2x + 20 = 50cm}$

$\implies\sf{2x = 50 - 20}$

$\implies\sf{2x = 30}$

$\implies\sf{x = \frac{\cancel{30}}{\cancel2}}$

$\implies\sf{x = 15}$

${\sf{\underline{\underline{\red{hence}}}}}$

length of equal side of the triangle is 15cm

★$\sf\underbrace\red{more\: information}$★

☆ Formula Related To Triangle ☆

1) triangle ( normal)

⊱ area = $\sf{\frac{1}{2} × b × h}$

⊱ perimeter = a + b + c

2) Equilateral triangle

⊱ area = $\sf{\frac{\sqrt{3}}{4} × (side)²}$

⊱ perimeter = 3 × side

3) isosceles triangle

⊱ area = $\sf{\frac{3}{4} \sqrt{4b² - a²}}$

⊱ perimeter = $\sf{ a + 2b}$

4) right triangle

⊱ area = $\sf{\frac{ba}{2}}$

⊱ perimeter = $\sf{ a + b + c}$

Answer 2

GivEn:

• Traingle is isosceles
• Perimeter of triangle = 50cm
• unequal side of this triangle = 20cm

To finD:

• Length of equal Sides

To finD :

Given that triangle is isosceles so, two sides of this triangle will be of equal measures.

Now,

Supposing that one equal side is x. So, given two sides are equal so another equal side will be also equal to x.

We know that -

Perimeter of isosceles triangle = 2a + b

where :

• a = Length of one side from equal measure
• b = Length of unequal side

Let put the given values in this formula :-

Perimeter of isosceles triangle = 2a + b

=> 50 = 2x + 20

=> 2x = 50 - 20

=> 2x = 30

=> x = 30/2

=> x = 15cm

∴ Length of equal sides of triangle is 15cm each.

Hence,

Our final required answer :-

• First side of traingle = 20cm ••••( given)
• Second side of triangle = 15cm
• Third side of triangle = 15cm

Know more :-

1.) What is isosceles triangle?

=> Isosceles triangle is a type of triangle in which the length of two sides are equal and also, two angles opposite to two equal side are equal.

2.) Isosceles triangle useful formula :

• => Area of isosceles triangle :

1/2 × base × height

• Perimeter of isosceles triangle :

2a + b [a = length of equal side,b = length of unequal side]