Question

the cost of turfing a triangular field at the rate 5/– per m^2
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Answer 1

First of all the questions not finished,... but since I'm in the same grade your lucky

Sol:

Given sides of a triangle a = 40 m , b = 70 m , c = 90 m.

2S = a + b + c

S = ( a + b + c ) / 2 = ( 40 + 70 + 90 ) / 2 = 200 / 2 = 100.

Area of a triangle =  

√

S(S - a)(S - b)(S - c)

=  

√

100(100 -40)(100 - 70)(100 - 90)  

=  

√

100x60x30x10  

= 100 x 6√5

= 600 x 2.236 = 1341.6 m2

Given cost of of turfing a triangular field at the rate of rupees 5 per m2.

∴ total cost = 1341.6 x 5 = Rs.6708