Question

find the area of an eqalateral triangle whose perimeter is 60 cm sq find the cost of leveling a ground in the form of a triangle with side 40cm,70cm and 90cm at 4rupees per sq m

Answer 1

I think You've asked two questions so I'm gonna answer Separately.

First one.

Given Perimeter = 60cm.
Therefore,side

Perimeter of an equilateral triangle = 3a
60 = 3a
60/3 = a
a = 20cm.

Semi perimeter = a + b + c/
= 20 + 20 + 20/2
=60/2
=30cm.
Hence Area using Heron's Formula:

=√s(s-a)(s-b)(s-c)
=√30(30-20)(30-20)(30-20)
=√30×10×10×10
=√2×3×5×2×5×2×5×2×5
=2×2×5×5√3
=100√3cm^2.


Second one.
Semi perimeter = a + b + c/2
= 40 + 70 + 90/2
= 200/2
= 100cm.

Hence,area = √s(s-a)(s-b)(s-c)
=√100(100-40)(100-90)(100-40)
=√100×60×10×60
=√10×10×10×6×10×10×6
=10×10×6√10
=600√10cm^2

Therefore,Cost = 600√10 × 4
= 600 × 3.16 × 4
= Rs.7584.


PEACE OUT