4 feet
An equilateral triangle that has a perimeter of 57 feet has three equal sides of 19 feet.
Equilateral triangles have all sides the same length, and to get the perimeter, you add all the side lengths. 15+15+15=45
Perimeter = 3*8 = 24 feet
The maximum area is just under 3.9 sq feet [exactly (3/2)2*sqrt(3) sq ft] - an area that is attained by an equilateral triangle. Since the question specifies an isosceles triangle, the answer is very very slightly less than that.
The length is 3 feet
An equilateral triangle that has a perimeter of 57 feet has three equal sides of 19 feet.
Find the area of an equilateral triangle if its perimeter is 18 ft
52+52+52 156
Equilateral triangles have all sides the same length, and to get the perimeter, you add all the side lengths. 15+15+15=45
Perimeter = 3*8 = 24 feet
389.711 ft2
8 feet x 3 sides = 24 foot perimeter.
24 feet (8 x 3)
It works out as 22.335 feet rounded to three decimal places
Losers calculate it yourself
Length of longer leg = 9.4 tan 60 = 16.28 feet Length of hypotenuse = 9.4 ÷ cos 60 = 18.8 feet Perimeter of triangle = 9.4 + 16.28 + 18.8 = 44.48 feet
Just add together the length of the sides to get the perimeter. If the shape is 5 feet by 5 feet by 8 feet, just add together the sides: 5 + 5 + 8 = 18 feet.