I am stumped please help me??????

Question

The problem is

The lenght of one of the equal legs of an isosceles triangle is 8 cm less than 4 times the lenght of the base. If the perimeter is 29 cm, find the lenght of one of the equal legs.


I keep getting 12 is that right .

Please help me I am so lost. Thank you so very much for your help in advance.

Answer 1

let the base be x and two equal legs be 4x-8

Therefore Perimeter= 4x-8+4x-8+x
Putting the perimeter:

29=4x-8+4x-8+x
29+16=9x
x=45/9
x=5

Therefore 4x-8=20-8
=12
Lenght of the equal sides=12cm

Hmmmmmmmmmmmm....... U are right.

I think we will need Einstien to prove u wrong :-)

Answer 2

You've got it exactly right. One way to check it would be to review the requirements from the problem.

First, if 12 is one of the equal legs then obviously the other leg must be 12. Total perimeter equals 29. Therefore, 29-12-12 = 5 . So, the base must be equal to 5.

Next, does 4*b - 8 = 12, the length of the equal leg

4*b - 8 = 4*5 - 8 = 20-8 = 12 , so yes it does.

Therefore, your answer must be right.

By equation, you would set 2*l + b = 29
and l = 4b - 8 as your two equations with 2 unknowns. By solving these two equations, you will get the answers above.

Answer 3

Yes, you are.

let the base be = x
since the length of the one side is 8cm less than 4 times the L of the base, so the side would be = 4x-8

the equation of the perimeter would then be:
2(4x-8)+x = 29

solving the equation, you will get the value of x=5

substituting x with the value of 5 in 4x-8, you will get 12 as the length of the other equal side, which is 12.

Answer 4

Let

x = length of base
y = length of equal legs
p = perimeter

Given

y = 4x - 8
p = 29

Find y.

We have

y = 4x - 8
p = x + 2y = x + 2(4x - 8) = x + 8x - 16 = 9x - 16 = 29
9x = 45
x = 45/9 = 5

y = 4x - 8 = 4*5 - 8 = 20 - 8 = 12 cm

So you are correct.

Answer 5

The answer is 12. How?

Let x = 1 of the equal sides
b = base.

So, x = 4b-8 ....................(1)
and,
2x+b=29..........................(2)

You now have 2 simultaneous equations, make x the subject of the formula for equation2.

x = (29-b)/2

therefore, 4b-8=(29-b)/2
8b-16=29-b
b = 5

If b=5,

x=4(5)-8
= 12

Answer 6

l=4b-8
p=2l+b
p=2(4b-8)+b
p=29=8b-16+b add 16 to each side
45=9b divide by 9
b=5cm
l=4b-9=4*5-8=20-8=12
p=12+12+5=29

I got l=9. Without seeing your work, I don't know where you made your mistake.