Answer:
3.897
Step-by-step explanation:
equilateral triangles are also equiangular, meaning the have equal angles.
Triangle sum theory says that angles of a triangle add up to 180.
That means each angle is 60.
A = bh/2
You need the (h). The base of is 3. Perimeter = 9, so each side is 3
Draw a perpendicular line for the height. The line cuts the base in half (1.5)
Using trigonometry you can find the height.
tan 60° = h/1.5
h = height, 1.5 is half of 3, 60° is the base angle.
multiply each side by 1.5
1.5(tan 60°) = h
h=2.598
then substitute h into formula
A= <u>(2.598)(3) </u>
2
A = 3.897 rounded