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Question
Find the area of an isosceles triangle with perimeter is 36 cm and the base is 16 cm.
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Solution
Perimeter of triangle = a + b + c
36 = 2a + 16
2a = 36 - 16
2a = 20
a = `20/2`
a = 10
Here, It is given that,
a = equal sides = 10 cm
b = base = 16 cm
Area of is isoscles triangle = `"b"/4 sqrt(4"a"^2 - "b"^2)`
`= 16/4 sqrt(4 (10)^2 - (16)^2)`
`= 4 sqrt(4 xx 100 - 256)`
`= 4 sqrt(400 - 256)`
`= 4 sqrt144`
= `4 xx 12`
= 48 cm2
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