SOLUTION: Find the altitude of an equilateral triangle that has side lengths of 4y. Express your answer in simplest radical form. I am a homeschooling mom and don't remeber how to do this

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The interior angles of an equilateral triangle
are 60-60-60, which adds up to
180 degrees, as they should.
The altitude divides the triangle into two
30-60-90 triangles, with the altitude being
opposite the 60 degree angle.
Call the altitude
In this right triangle, ,
and

Solve for

You can put this solution on YOUR website!

If you construct an altitude of an equilateral triangle, then the altitude forms a right angle with the base. That means that you have now formed two 30-60-90 triangles, i.e. right triangles where the hypotenuse is one side of the equilateral triangle and the short leg is exactly one-half the measure of the hypotenuse. Now having a hypotenuse of 4 and a short leg of 2, we can use Pythagoras to calculate the measure of the long leg which is the same as the altitude of the equilateral triangle:






In general, if the measure of the length of a side of an equilateral triangle is , then the measure of an altitude is:


John