Question

please solve it copy.​

Answer 1

Solution

Given :-

• Base of isosceles triangle = 20 cm
• Each of equal side = 26 cm

Find :-

• Area of isosceles triangle .

Explanation

Using Formula

$\star\boxed{\underline{\tt{\red{\:Height_{issosceles\:triangle}\:=\:\sqrt{(a^2\:-\dfrac{b^2}{4})}}}}}$

$\star\boxed{\underline{\tt{\blue{\:Area_{issosceles\:triangle}\:=\:\dfrac{1}{2}\times\:Base\:\times\:Height}}}}$

Let,

Here, ∆ABC be a isosceles triangle.

• Base (BC)= 20 cm = b
• Equal two side(AB)= (CA) = 26 cm = a
• Height = H.

First Calculate Height,

➠ Height of isosceles triangle(H) = √[a² - (b²/4)]

➠ Height of isosceles triangle(H) = √[(26)² - (20²/4)]

➠ Height of isosceles triangle(H) = √[676 - 400/4]

➠ Height of isosceles triangle(H) = √[ 676 - 100]

➠ Height of isosceles triangle(H) = √(576)

➠ Height of isosceles triangle(H) = 24 cm

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Now Calculate Area,

➠ Area of isosceles triangle = 1/2 × Base × Height

➠ Area of isosceles triangle = 1/2 × 20 × 24

➠ Area of isosceles triangle = 10 × 24

➠ Area of isosceles triangle = 240 cm²

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Hence

• Area will be isosceles triangle = 240 cm²

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