Question

A traffic signal board is an isosceles triangle with equal side is 60 cm and perimeter is 200 cm .Find the area of signal board ?? pls respond

Answer 1

Answer:

2400cm²

Step-by-step explanation:

area of triangle= ½×b×h

~h=80²/60²(by using Pythagoras theorem)

~h=6400/3600

~h=16/9

~area of ∆=½×80×60

~area of ∆=40×60

~area of ∆=2400cm²

Answer 2

Answer:

let abc be an isosceles triangle

let the equal sides of triangle abc be ab and ac

i.e., AB = BC

= 60cm

Given : perimeter = 200 cm

AB + BC + AC = 200

60 + 60 + AC = 200

AC. = 200 - 120

= 80 cm

Area of the signal board

( by using heron's formula)

s= a + b + c /2.

(here, a=60cm, b=60cm , c=80cm )

= 60 + 60 + 80 / 2

= 200 /2

= 100

√s (s- a) (s -b) ( s - c)

= √ 100 (100-60) (100-60) (100-80)

= √ 100 ×40×40×20

=. 40 √ 100×20

= 40 √ 20×5×20

= 40 ×20 √5

= 800 √5 cm2

hence , the area = 800 √5 cm2

Hope this ans would help you

Thank you ☺️☺️