A triangular park ABC has sides 120cm,80cm and 50cm.A gardener Dhania has to put a fence all around it ...?

Question

A triangular park ABC has sides 120cm,80cm and 50cm.A gardener Dania 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 rate of RS 20 per metre leaving a space 3m wide for a gate on one side.




I can find the area but how do i find the cost?

Answer 1

Are you sure you don't mean meters rather than centimeters? There's not room enough for a 3 meter gate otherwise. :)

Okay, what you need is the total perimeter (sum of all the sides). But subtract off 3m for the gate.

Once you have the total perimeter (250m) less the gate (247m), multiply this by the cost per meter.

247m x RS 20/m = RS 4,940

And while I'm at it... what method did you use to solve the area. I would use Heron's formula. The formula is:
A = sqrt[ s (s-a) (s-b) (s-c) ]

Where s is the "semi-perimeter" and a, b and c are the lengths of the sides.

s = (a+b+c)/2
s = (120+80+50)/2
s = (250)/2
s = 125

A = sqrt[ 125 * (125-120) * (125-80) * (125-50) ]
A = sqrt[ 125 * 5 * 45 * 75 ]
A = sqrt( 2109375 )
A ≈ 1,452 m²

Answer 2

The area is the amount of grass she needs to plant.

The fencing requires the perimeter. These measurements sure make a small, park! Anyway, you add them up, convert to meters, subtract 3, and multiply by 20.

If these side measurements are correctly in centimeters, the gate is wider than any side. The other 2 sides total 1.3 meters, multiplying that by 20=RS 26 for fencing with barbed wire.

If the side measurements are in meters, the perimeter is 250 meters, subtract 3 for the gate, and you get 247 meters, multiply that by 20=RS 4940 for fencing with barbed wire.

Answer 3

Abc Gardener