Question

1. An isosceles triangle has perimeter 30 cm and each of the equal sides is 12 cm. Find the area of
the triangle.
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Answer 1

Step-by-step explanation:

Length of the equal sides = 12cm

Perimeter of the triangle = 30cm

Length of the third side = 30 - (12+12) cm = 6cm

Semi perimeter of the triangle(s) = 30/2 cm = 15cm

Using heron's formula,

Area of the triangle = √s (s-a) (s-b) (s-c)

                                       = √15(15 - 12) (15 - 12) (15 - 6)cm2

                                       = √15 × 3 × 3 × 9 cm2

                                       = 9√15 cm2

Answer 2

Step-by-step explanation:

perimetr of triangle =a+b+c=30

a+b=12+12=24

so,c=30-(a+b)= 30-24=6

height =144 -9=√134

ar of triangle=1/2×b×h

1/2×6×√135

=3×√135

=34.85sq.cm. because√135=11.61