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Question
Find the area of a triangle, whose sides are :
21 m, 28 m, and 35 m
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Solution
Sides of ∆ are
a = 21 m
b = 28 m
c = 35 m
S = `(a + b + c)/2 = (21 + 28 + 35)/2`
= `84/2 = 42`
area of Δ = `sqrt(S(S - a)(S - b)(S - c))`
= `sqrt(42(42 - 21)(42 - 28)(42 - 35))`
= `sqrt(42 xx 21 xx 14 xx 7)`
= `sqrt(7 xx 3 xx 2 xx 3 xx 7 xx 2 xx 7 xx 7)`
= `sqrt(7 xx 7 xx 7 xx 7 xx 3 xx 3 xx 2 xx 2)`
= `7 xx 7 xx 3 xx 2 = 294 "m"^2`
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