Question

Find area of a isosceles triangle whose perimeter is 11cm and base 5cm

Answer 1

wait. I am putting in note...

perimeter= side +side +side
=5cm+X+x cm
=5+2x
x =2.5cm

in isosceles triangle two side are equal except base.

so, the sides are = 5cm , 2.5cm , 2.5cm

area of triangle= 1/2×b×h

base =5cm

height =?

by Pythagores theorem,

c=✓b^2+✓a^2
c=5cm+2.5cm
c= 7.5cm

area of the triangle
=1/2×b×h
=1/2×5cm×7.5cm
=1/2×37.5
=375/10×1/2
=375/20
=18.75

therefore the area of the triangle is 18.75sq.units


I hope my helping hand will help you ..