Question

the sides of a triangle are 80cm 100cm and 140cm. determine the radius of the inscribed circle

Answer 1

We need a picture of the triangle inscribing the circle.

Answer 2

you can solve for radius by equating areas
find area of triangle
then set it equal to ar+br+cr which also represents area of triangle

a+b = 140
a+c = 100
b+c = 80

--> a=80, b =60, c = 20

so you have:
A = 160r --> r = A/160 where A is area of triangle