Question

if the perimeter of an equilateral traingle is 60 cm then what is its area​

Answer 1

Answer:

Given

perimeter =60 cm

semi perimeter =

2

60

=30 cm.

Therefore the length of each side.

a+a+a=60

⇒3a=60

⇒a=

3

60

⇒a=20

∴ Area =

s(s−a)(s−b)(s−c)

⇒ Area =

30(30−20)(30−20)(30−20)

⇒ Area =

30×10×10×10

⇒ Area =

3×10×10×10×10

⇒ Area =10×10

3

⇒ Area = 100

3

cm

2

∴ so, the answer is D. 100

3

cm

2