Question

The base of an isosceles triangle is 20cm and its perimeter is 42cm.
Find its area.
​

Answer 1

Answer:

a=20

b=11

c=11. (42-20=22){(22÷2=11)this is a n isosceles triangle}

s=21

area= √s(s-a)(s-b)(s-c)

=√21(21-20)(21-11)(21-11)

=√21(1)(10)(10)

=10√21cm sq. is the area

hope it will help you