The length of AB is ___ inches to the nearest tenth of an inch. ( Enter only the number.)

https://courseplayer.avalearning.com/CourseFiles/Questions/835114/Gears.png

Question

The length of AB is ___ inches to the nearest tenth of an inch. ( Enter only the number.)

https://courseplayer.avalearning.com/CourseFiles/Questions/835114/Gears.png

anonymous · Answer

@perl @Sepeario

sepeario · Answer

How can I tell the answer? There are no values written on the diagram.

anonymous · Answer

Sorry, The diagram shows the gears of a bicycle. AD = 5 inches, and BC = 3 inches. CD, the length of the chain between the gears, is 17 inches.

anonymous · Answer

@Sepeario

sepeario · Answer

Have you heard of Pythagoras' Theorem?

anonymous · Answer

No

sepeario · Answer

It is a triangle side theorem stating $$a ^{2}+b ^{2}=c ^{2}$$ where a,b are the two smaller sides and c is the longest side.

anonymous · Answer

It would be 17.1 then right?

sepeario · Answer

BE must be 17 since it is the same as CD. AE = AD-CB. Hence AE = 2. Using the theorem I have just taught you, $$2^{2}+17^{2}=AB ^{2}=293$$

sepeario · Answer

Yes it is 17.1. Well done. Are you sure you've never heard of Pythagoras before?

anonymous · Answer

I think I learned it a while ago and forgot the name!

sepeario · Answer

haha k :)