Bianca calculated the height of the equilateral triangle with side lengths of 10.

tangent (30) = StartFraction 5 Over h EndFraction An equilateral triangle with side lengths of 10 is shown. A bisector is drawn to split the side into 2 equal parts and splits the angle into 2 30 degree segments.
Then, she used the formula for area of a triangle to approximate its area, as shown below.

A = one-half b h. = one-half (10) (8.7). = 43.5 units squared.

Calculate the area of the equilateral triangle using the formula for area of a regular polygon, and compare it to Bianca’s answer.

The apothem, rounded to the nearest tenth, is
_____ units.

The perimeter of the equilateral triangle is ______
units.

Therefore, the area of the equilateral triangle is ________
, or approximately 43.5 units2.

The calculated areas are ______________
.


ANSWER is
- 2.9
- 30
- 1/2 (2.9) (30)
- the same, despite using different different formulas