## ashleyb 2 years ago can someone please help me with this geometry question?? in right triangle ACE, line BD is parallel to line AE, and line BD is perpendicular to line EC at D. the length of line BD is 3 feet, and the length of line CD is 4 feet. what is the length in feet of line AE

1. ashleyb

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2. jim_thompson5910

First you need to find BC

3. jim_thompson5910

do you know how to do this?

4. ashleyb

is bc 5?

5. jim_thompson5910

good

6. jim_thompson5910

now set up the following ratio AE/BD = AC/BC x/3 = 20/5 solve for x

7. ashleyb

12

8. jim_thompson5910

you got it

9. ashleyb

but why do u set up a ratio?

10. jim_thompson5910

because the ratio of AE to BD is the same as the ratio of AC to BC

11. jim_thompson5910

basically, to go from BD to AE, you multiply by 4 to go from BC to AC, you also multiply by 4

12. jim_thompson5910

so the bigger triangle has side lengths that are 4 times larger than the smaller triangle

13. jim_thompson5910

setting up a ratio is similar to that idea

14. ashleyb

oh ok i get it! thank you for your help

15. jim_thompson5910

np