Question

two sides of a triangle are 18cm and 13cm. the perimeter of triangle is 42 cm. find its 3rd side.​

Answer 1

Answer:

11 cm

Step-by-step explanation:

42-18+13=x

42-31=x

x= 11cm

Answer 2

Step-by-step explanation:

let the 3rd side be x

then

18 cm+13cm+x =42

31cm + x =42cm

x= 42-31

x = 11