Bianca calculated the height of the equilateral triangle with side lengths of 10. tan(30) h = 8.7 5 ns 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. 30 The perimeter of the equilateral triangle is Therefore, the area of the equilateral triangle is or approximately 43.5 units. The calculated areas are units. Then, she used the formula for area of a triangle to approximate its area, as shown below. A = bh (10)(8.7) = 43.5 units2