Challenge: Calculating a rig change

[wingssail]

Here is a little brain teaser:

I needed to rake my mast back to get a little more weather helm (it helps me go to windward).

I lengthened the forestay by extending the turnbuckle, which let the top of the mast move back.

I took in the slack in the backstay by the same method.

Now, say I let out 10" on the forestay, how far back did the top of the mast move?

I needed a quick and easy answer and I found one which took about 3 minutes.

What is it?

Clue: use trig and don't worry if the answer is imprecise.

[wingssail]

Originally Posted by wingssail

Here is a little brain teaser:

I needed to rake my mast back to get a little more weather helm (it helps me go to windward).

I lengthened the forestay by extending the turnbuckle, which let the top of the mast move back.

I took in the slack in the backstay by the same method.

Now, say I let out 10" on the forestay, how far back did the top of the mast move?

I needed a quick and easy answer and I found one which took about 3 minutes.

What is it?

Clue: use trig and don't worry if the answer is imprecise.

(BTW, my mast is 60ft and my foredeck is 16ft)

[tamicatana]

Pythagoras. It's a triangle.