Question

A triangular park ABC has sides 120m, 80m and 50m (see Fig. 12.7). A
gardener Dhania has to put a fence all around it and also plant grass inside. How
much area does she need to plant? Find the cost of fencing it with barbed wire at the
rate of 20 per metre leaving a space 3m wide for a gate on one side.


SOLVE WITH FULL EXPLANATION ​

Answer 1

Step-by-step explanation:

Given, Sides are 120m, 80m and 50m.

Then,

Semiperimeter(s) = (120 + 80 + 50)/2 = 125 m.

Now,

Area = √s(s - a)(s - b)(s - c)

       = √125 * (125 - 120)(125 - 80)(125 - 50)

       = √125 * 75 * 45 * 5

      = 375√15 m²

Number of metres to be fenced = 120 + 80 + 50 - 3 = 247 m.

Cost of fencine per metre = 20.

Cost of fencing park = 20 * 247 = 4940.

Therefore,

Area needed to plant = 375√15

Cost of fencing = 4940.

Hope it helps!

Answer 2

Answer:

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