SOLUTION: Find the area of an equilateral triangle that has a perimeter of 21 inches. Round the answer to one decimal place.
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Question 318522: Find the area of an equilateral triangle that has a perimeter of 21 inches. Round the answer to one decimal place.
Found 3 solutions by Earlsdon, mananth, Fombitz:
Answer by Earlsdon(6294) (Show Source): You can put this solution on YOUR website!
You could use Heron/Hero's formula for finding the area of a triangle when you know the lengths of the three sides, a, b, and c.
s = the semi-perimeter of the triangle.
= = Make the appropriate substitutions:
sq.in. (Rounded to one decimal place.)
Answer by mananth(16946) (Show Source): You can put this solution on YOUR website!
perimeter of equilateral triangle = 21
side = 7
s=21/2
area = sqrt{s(s-a)(s-b)(s-c)}
area=sqrt{21/2(21/2-7)^3}
area = 21.2 sq.in
Answer by Fombitz(32388) (Show Source): You can put this solution on YOUR website!
.
.
.
.
.
.
Find h using the Pythagorean theorem.
.
.
.
Find using the perimeter.
Substitute,
or approximately,
The area is 17.3 sq. inches.
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