Question

the perimeter of an isosceles triangle is 20 cm. if one of the equal sides is 19/4 cm long,find the measure of the third side.

Answer 1

let the third side will be x.
then,

$19 \div 4 + 19 \div 4 + x = 20 \\ 38 \div 4 + x = 20 \\ (38 + 4x) \div 4 = 20 \\ 38 + 4x = 80 \\ 4x = 80 - 38 \\ 5 \\4x = 42 \\ x = 42 \div 4$
x = 42/4
x=10.5cm

Answer 2

let the side be x. there are two equal side in isosceles triangle. if one of the equal side is 19/4 then other would also be 19/4. so we got equation, 20=19/4 +19/4 +x, 20=19/2 +x, x=20-19/2, x=21/2