Question

two side of triangle are 18 cm and 20 cm.If its perimeter is 50 cm,what is the length of its third side

Answer 1

let the sides be a, b and c

then

Perimeter=a+b+c

50=18+20+c

38+c=50

c=50-38=12

therefore, length of the third side is 12cm

Answer 2

Let the third side be Xcm
18+20+x= 50(given)
a+b+c=perimeter
X=50-38
X= 12cm