Question

the base of an isosceles is 10 cm and its perimeter is 30 cm find its equal side​

Answer 1

Answer:

Base of the isosceles triangle is 10 cm

One of its equal side is 13 cm, so the third side is also 13 cm

Now, the three sides are a=10,b=13,c=13

According to Hero's formula,

Area of a triangle, A=

s(s−a)(s−b)(s−c)

where,

s=

2

a+b+c

s=

2

10+13+13

=18

Now,

A=

18(18−10)(18−13)(18−13)

=

18(8)(5)(5)

=

9(16)(5)(5)

=3×4×5

=60cm

Answer 2

your answer is 8 cm

wait here is an example for u

Let the length of each equal sides of an isosceles triangle is x cm. then 3 rd side

will be (x+10) cm. long. Acordingly:-

x+x+(x+10)=30

3x=90

x=30

a=30cm . b=30cm. andc =40cm.

s=(30+30+40)/2=50.

Area =[s(s-a)(s-b)(s-c)]^1/2.

=[50.(50–30)(50–30)(50–40)]^1/2.

=[50×20×20×10]^1/2.

=[5×10×20×20×10]^1/2.

=200.(5)^1/2. sq.cm