Question

if the perimeter of of a triangle is 300cm and sides are 40cm, 150cm and x.

find the value of x.

Answer 1

Perimeter of triangle=sum of sides
300=40+150+x
300-190=x
x=110cm

Answer 2

$we \: know \: that \: the \: sum \:all \: three \: sides \: of \: a \: triangle \: = perimeter \: of \: the \: triangle$
$therefore \\ \\ 40 + 150 + x = 300 \\ \\ 190 + x = 300 \\ \\ x = 300 - 190 \\ \\ x = 110 \: cm$


hope it helps....