Mensuration, Ex 20D

Question

10. Find the area of an equilateral triangle each of whose sides measures (1) 18 cm, (ii) 20 cm. [Take √3=1.73]

Can anyone please answer the question which is visible? .....

Answer 1

barbie5878, hello

Ue the formula for the area of a triangle is equal to on-half the base times the height.

18² = 9² + h²  ==> h = \(9 \sqrt{3}\)  cm

So the area of the first equilateral triangle each of whose sides equals 18 cm is approximately 140.13 cm²

Using the same procedure for the second triangle we get a height of \(10 \sqrt{3}\) cm

And an area of approximately 173 cm² 

Please let me know if this helps...

Answer 2

Use formula (root 3 into a^2)/4