Question

Find the cost of painting if a triangular signboard of side 50cm,65cm and 65 cm at the rate of rs 7 per cm square​

Answer 1

Answer:

Rs. 10500, I think

Step-by-step explanation:

by heron's formula,

$\sqrt{s(s - a)(s - b)(s - c)}$

where , s=

$\frac{sum \: of \: all \: sides \: of \: triangle}{2}$

$= \frac{50 + 65 + 65}{2} = \frac{180}{2}$

s = 90

and a , b, c are sides of triangle , here 50 ,65 ,65 , respectively.

$\sqrt{90(90 - 50)(90 - 65)(90 - 65)} = \sqrt{90(40)(25)(25)} = \sqrt{2250000} = 1500$

hence ,area of triangle is 1500 cm^2

now rate of painting it = 1500×7

= Rs.10500

hope helps.

Happy New year

Answer 2

By heron formula

Root s( s- a)( s- b )( s- c)

where, s=

sum of all sides of triangle/2

50+65+65/2=180/2

s=90

and a, b, care sides of triangle , here 50, 65, 65, respectively.

root 90(90-50)(90-65)(90-65)=

root 90(40)(25)(25) = root 2250000=1500

hence , area of triangle is 1500 cm 2

now rate of painting it=1500×7

Rs.10500___