Question

in isoceles triangle has perimter 30cm and each of equal sides is 12cm. find the area of triangle.
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Answer 1

Answer:

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Step-by-step explanation:

9th

Maths

Heron's Formula

Area of a Triangle

An isosceles triangle has p...

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Asked on December 27, 2019 by

Barsha Sambyal

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

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ANSWER

Perimeter of isosceles triangle=30cm

Length of equal sides=12cm

Let third side of triangle=xcm

According to problem,

x+12+12=30

x+24=30

x=30−24

x=6

∴ Third side of triangle=6cm

Using Heron's formula

Area of triangle=

s(s−a)(s−b)(s−c)

sq. units

where s=

2

a+b+c

s=

2

30

=15

Area of triangle=

15(15−12)(15−12)(15−6)

cm

2

=

15×3×3×9

cm

2

=3×3×

15

cm

2

=9

15

cm

2

∴ Area of triangle=9

15

cm

2

.