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Question
The sides of a triangle are 21 cm, 17 cm, and 10 cm. Find its area.
Solution
Let a = 21 cm, b = 17 cm and c = 10 cm
∴ a + b + c
= 21 cm + 17 cm + 10 cm = 48 cm
s =`"a + b + c"/2=48/2` = 24 cm
Area of the triangle
= `sqrt(s(s-a)(s-b)(s-c))`
= `sqrt(24(24-21)(24-17)(24-10))`
= `sqrt(24xx3xx7xx14)`
= `sqrt(2xx2xx2xx3xx3xx7xx2xx7)`
= 2 × 2 × 3 × 7
= 84 cm2
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