Question

The cost of laying grass in triangular field offsides 50m, 65m and 65m at the rate of ₹ 7 per m² is.........

₹15000
₹10050
₹10500
₹10005
​

Answer 1

Answer:

a=50 m

b=65 m

c=65m

s=a+b+/2

=50+65+65/2

=180/2

∴Area of a triangular field

=√s(s−a)(s−b)(s−c)    [by Heron's formula]

=√90(90−50)(90−65)(90−65)

=√90×40×25×25

=3×2×10×25

=6×250

=1500m²

∵cost of laying grass per 1m² = Rs. 7

∵cost of laying grass per 1500m²=7×1500

= Rs. 10500

Hence, the cost of laying grass in a triangular field is Rs. 10500

Answer 2

Given:-

Sides of triangle are 50m ,65m and 65m.

To find:-

The cost of laying grass  at the rate of ₹ 7 per m² .

Solution:-

• To calculate the area of given triangle we will use the heron's formula :

    Area =√s(s-a)(s-b)(s-c)

Where  s = a+b+c/2 .

And a,b,c are sides of triangle.  

Now substitute the values :

⇒ s = 50+65+65 /2

⇒ s= 90.

Now,

Area = √90(90-50)(90-65)(90-65)

⇒ Area = 1500 sq.m

Now,

⇒  cost of laying 1 sq.m. = rs.7

⇒ So, cost of laying 1 sq.m. =  1500 × 7 = Rs. 10500.

Hence, the ans is Rs.10500.

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