Each of the two congruent sides of an isosceles triangle is 8 in. less than twice the base. THe perimeter of the triangle is 74 in. WHat is the lenght of the base?
2007-10-03 15:25:33 · 4 answers · asked by ExpertTechAnswers 2 in Science & Mathematics ➔ Mathematics
c +8 = 2b
b + c + c = 74 = b + 2c = b + 2 (2b - 8) = b + 4b - 16 = 5b - 16
5b = 90
b = 18
2007-10-03 15:31:23 · answer #1 · answered by Beardo 7 · 0⤊ 0⤋
let the base be 'x'
then each side will be '2x-8'
As perimeter is sum of the three sides, So:
x+ 2x-8+2x-8= 74
=> 5x-16= 74
=> 5x= 74 +16= 90
=> x = 18
proof:
as thebase (x) is 18 and each side is2x-8 = 2*18 - 8= 28.
so perimeter will be 28+28+18=74=given perimeter.
2007-10-03 15:37:22 · answer #2 · answered by Gurpreet S 1 · 0⤊ 0⤋
You know you have 2 sides that are each 8 inches less then 2x the base. Let's call the base B.
Your sides are A for our purposes.
a=2b-8 (we're told that....)
our total triangle is 74....
Side 1 =2b-8
side 2=2b-8
side 3= b
74=2b-8+2b-8+b
74=5b-16
90=5b
18=b
so side b is 18 and the other sides are each 28.
2007-10-03 15:34:19 · answer #3 · answered by Snoopy 5 · 0⤊ 0⤋
Your triangle has three sides: a, b, and c.
Isosceles triangle means a = b
Perimeter = a + b + c
74 = 2a + c
The first sentence tells me: a = 2c - 8
74 = 2(2c - 8) + c
74 = 4c - 16 + c
90 = 5c
c = 19
The base is 19 in long
2007-10-03 15:30:15 · answer #4 · answered by lhvinny 7 · 0⤊ 1⤋