if line segment AC=120ft and the ratio of line AB:BC =3/5 - what is the length of line AB ?
I set up the problem up as X:120 & 3:5
3x120= 360 and divided 5 into 360 = 72ft
but the answer in the book is 45ft
help!
To find the length of line AB, we can set up a proportion using the given information. Let's denote the length of AB as x.
The ratio of line AB to line BC is given as 3:5, which means:
AB/BC = 3/5
Since AC is given as 120ft and BC is a part of it, we can find BC by subtracting AB from AC:
BC = AC - AB
BC = 120ft - x
Now, we can substitute AB/BC with x/(120 - x) in the proportion:
x/(120 - x) = 3/5
Cross multiplying, we get:
5x = 3(120 - x)
5x = 360 - 3x
Combining like terms:
8x = 360
Dividing both sides by 8:
x = 45
So, the length of line AB is 45ft.
Your calculation seems to be incorrect. It appears that you set up the equation as X:120 and 3:5, which should be the other way around: AB:AC and 3:5. Please recheck your steps and set up the problem as AB:AC and 3:5, then solve for AB.