Answer:
20√3 cm
Step-by-step explanation:
Altitude of an equilateral triangle splits it into 2 equal right triangles, it bisects the base and the angle opposite to the base.
<u>Let the altitude be x. Then as per Pythagorean theorem:</u>
- x² = 40² - (40/2)²
- x²= 1600 -400
- x²= 1200
- x= √1200
- x= 20√3 cm
<u>Correct choice is</u> the second one
Step-by-step explanation:

Square both sides of the equation.


Answer:
x1=3 x2=-5
BUT x1=3 is not an answer because it doesnt respects the range on the original ecuation, so x2=-5 is the solution
Step-by-step explanation: