Question

The length of a side of an equilateral triangle is 40cm. what is the length of the altitude of the triangle?

20√2 cm
20√3 cm
4√5 cm
6√5 cm​

Answer 1

20√3 cm

Explanation:

Altitude of an equilateral triangle splits it into 2 equal right triangles, it bisects the base and the angle opposite to the base.

Let the altitude be x. Then as per Pythagorean theorem:

• x² = 40² - (40/2)²
• x²= 1600 -400
• x²= 1200
• x= √1200
• x= 20√3 cm

Correct choice is the second one