Question

12. The perimeter of an isosceles triangle is 20¾cm.if one of its equal sides is 2⅚cm, find the third side​

Answer 1

Given

✭ Perimeter of an isosceles triangle is 20¾ cm

✭ Equal sides are 2⅚ cm

To Find

◈ The base of the triangle?

Solution

Concept

So here we shall use the formula A = P-2B to get our Answer. We got this formula onna simple basis, in an isosceles triangle two sides are equal and perimeter is equal to the sum of all the sides so if we subtract the equal sides from the perimeter we get the length of the un equal side!!

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We know that the base of an isosceles triangle is given by,

A = P-2B

• A = Unequal Side = ?
• P = Perimeter = 20¾ cm = 83/4
• B = Equal Sides = 2⅚ cm = 17/6

Substituting the given values,

➝ A = P-2B

➝ A = 83/4 - 2(17/6)

➝ A = 83/4 - 17/3

«« LCM of 4 & 3 is 12 »»

➝ A = (249/12) - (68/12)

➝ A = (249-68)/12

➝ A = 181/12 cm

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