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The area of an isosceles triangle having base 2 cm and the length of one of the equal sides 4 cm, is ______.

#### Options

`sqrt(15)` cm

^{2}`sqrt(15/2)` cm

^{2}`2sqrt(15)` cm

^{2}`4sqrt(15)` cm

^{2}

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#### Solution

The area of an isosceles triangle having base 2 cm and the length of one of the equal sides 4 cm, is **`sqrt(15)` cm ^{2}**.

**Explanation: **

a = 2, b = 4, c = 4

s = `(a + b + c)/2`

⇒ s = `(2 + 4 + 4)/2 = 10/2` = 5.

Area (Δ) = `sqrt(s(s - a)(s - b)(s - c))`

⇒ Area (Δ) = `sqrt(5(5 - 2)(5 - 4)(5 - 4))`

⇒ Area (Δ) = `sqrt(5 xx 3 xx 1 xx 1`

⇒ Area (Δ) = `sqrt(15)` cm^{2}

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