If the perimeter is 29cm, find the length of one of the equal legs.
2006-12-10 04:39:11 · 4 answers · asked by Teresa A 1 in Science & Mathematics ➔ Mathematics
Let b = base of isosceles triangle.
Then, 4b - 8 = length of the two other sides.
Perimeter of a triangle is equal to the sum of all the sides, therefore
P = (base) + (equal leg) + (equal leg)
P = b + (4b - 8) + (4b - 8)
But, P = 29, so
29 = b + (4b - 8) + (4b - 8)
Group like terms, getting
29 = 9b - 16
45 = 9b
Therefore, b = 5
But we want the length of one of the equal legs. Fortunately enough, we know what that is; it's equal to 4b - 8
Therefore, 4b - 8 = 4(5) - 8 = 20 - 8 = 12
2006-12-10 04:48:49 · answer #1 · answered by Puggy 7 · 0⤊ 1⤋
Let the length of base=x cm
length of one of the equal side=4x-8 cm
2[4x-8]+x=29 cm
9x-45=0
x=5 cm
one of the equal side
=4x-8
=4*5 -8
=12cm
2006-12-10 13:05:50 · answer #2 · answered by openpsychy 6 · 1⤊ 1⤋
If all sides start out as x, then you have x (the base) + 2(4x-8). I'm not sure about the next step, but I believe you would set it equal to 29, and solve for x.
x + 2(4x-8) = 29.
2006-12-10 12:44:54 · answer #3 · answered by Anonymous · 0⤊ 2⤋
X = LENGTH OF BASE
X + 2(4X - 8) = 29
X + 8X - 16 = 29
9X - 16 = 29
9X = 45
X = 5
BASE = 5 CM, SIDES = 12 CM EACH
2006-12-10 12:45:48 · answer #4 · answered by MisterRE 3 · 1⤊ 0⤋