The sides of a triangle are `7\ c m ,\ 9\ c m\ a n d\ 14\ c mdot` Its area is
`12sqrt(5)\ c m^2` (b) `12sqrt(3)\ c m^2` `24sqrt(5)\ c m^2` (d) `63\ c m^2`

Explanation

"Let the sides of the triangles be `a=7cm, b=9cm and c=14cm`

semiperimeter of the triangle, `s=(a+b+c)/2`

`s=(7+9+14)/2`

`s=15`

Now, area of triangle by using heron's formula = `(ssqrt((s-a)(s-b)(s-c)))`

`(15sqrt((15-7)(15-9)(15-14)))`

`sqrt720 cm^2`

`12sqrt5cm^2`

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