Perimeter Of A Right Angled Triangle.

[Tilly2]

I'm asking this early, as I am embarrassed to have to ask.

How do you find the length of the 'long' side of a right angled triangle?
So, if the length is 2 and the height is 3, how do you find the length of the diagonal side?

I really, really can't remember.

I have in my head, a squared+b squared = c squared.

Is it the square on the hypotenuse thingy?

[factor-fiction]

Pythagoras' Theorem (I never agreed with the apostrophe going there)

[sandyRoe]

The square on the hypotheneuse is equal to the sum of the other two. in this case the square root of 13 is the length

[factor-fiction]

If D is the length of the diagonal then D² = 2² + 3²= 13, so D= √13

[Tilly2]

Thank you, factor but can you remind me how to apply Pythagoras' Theorem.

[sandyRoe]

3.605

[factor-fiction]

Gosh I'm a slow typer- shouldn't have messed about looking for the ² symbol

[factor-fiction]

Anyway, the perimeter is therefore 5+√13

[Tilly2]

Thank you both. That's put me out of my misery.

[Tilly2]

By the way, factor, there's nothing wrong with Pythagoras' apostrophe.:-)

(Unless, of course, it wasn't his Theorem)

[woofgang]

:-)

http://www.youtube.com/watch?v=oeRCsAGQVy8

[Tilly2]

Thanks, woofgang. That brought it all back.

[factor-fiction]

Hi tilly- it's the positioning I don't understand- why isn't it Pythagoras's theorem, because that's how we say it.

[FredPuli43]

Strictly it is Pythagoras's theorem, just as the the street is St James's, because a name ending in S has " 's " in the possessive, but the practice of putting " s' " is so common now that the rule is largely in abeyance.

[factor-fiction]

Hi Fred- i know it's more common now to say St Thomas' (although some rightly keep the St Thomas's), but there seems to be a rule that for major historical figures the apostrophe goes after the S- text books usually give Achilles' heel, Jesus' disciples, Pythagoras' theorem as examples. Yet we would write Jess's coat rather than Jess' coat, wouldn't we? It just seems inconsistent to me.

I have noticed a trend now to putting the apostrophe after the S in other words ending in S- eh the boss' wife, the business' core values. That is surely wrong

[Tilly2]

According to 'Practical English Usage'. Michael Swan

pg 441 ..........but with singular classical (ancient Greek and Roman) names ending in s' we sometimes pronounce a possessive 's even when it is not written.

Oedipus' little problem.

[factor-fiction]

Thanks, Tilly- that's what I remember being taught and what I read in Fowler. I don't see the logic, that's all.

[jake-the-peg]

You were looking for logic in the English language?

[Tilly2]

No, jake. I was looking for the answer to a maths problem.

[factor-fiction]

I think jake's comment was for me, tilly.