28 Replies Latest reply on Nov 7, 2013 5:13 AM by Tom Greca

# Best way to make triangle?

Hi,

What's the best/quickest/simplest way to draw an equilateral triangle in

InDesign?

Thanks,

Ariel

• ###### 1. Re: Best way to make triangle?

Do it in Illlustrator, copy, paste in ID.

• ###### 2. Re: Best way to make triangle?

Not really.

ID also has a polygon tool hidden under the other shape tools. Double-click it and you can set the number of sides to 3, Hold the shift key while you drag and that should do it.

• ###### 3. Re: Best way to make triangle?

Nah -- this should be doable in ID. Anyway, how would you do it in

Illustrator, for that matter?

Something's gone funny with my geometry. I was thinking of something

like this:

Triangle T has three sides, each of which is length a. Hence T is an

equilateral triangle.

If you divide that triangle into 2 such that you get two right-angled

triangled (ie where one of the angles if 90deg) T1 and T2, the lengths

of the sides of T1 are: 1/2a, a, and x. We need to find x.

Now, by Pythagoras's theorem:

(1/2a)2 + x2 = a^2

So: x2 = (1/2a)2

Hence: x = (√1/2)a

So x = .707a

So I thought:

Draw a rectangle whose width is 10 cm, and whose height is 7.07 cm.

Convert that to a triangle with the pathfinder tool.

Voila!

But no. Close, but not quite. The sides are not entirely equal.

So something's wrong with my algebra or maths.

What?

Ariel

• ###### 4. Re: Best way to make triangle?

Polygon Tool, Width: 1 and Height .866

• ###### 5. Re: Best way to make triangle?

You had me fooled Peter!

Thanks for the suggestion -- just measured and that does the trick.

Ariel

• ###### 6. Re: Best way to make triangle?

Thanks Jeffrey. Any idea what is wrong with my calculations?

• ###### 7. Re: Best way to make triangle?

The ratio of the base to the height of an equilateral triangle is the sqare root of 3  x the base divided by 2. So for a 2" equialteral the height is (1.732 x 2)/2

• ###### 8. Re: Best way to make triangle?

Arïel wrote:

Anyway, how would you do it in

Illustrator, for that matter?

Essentially the same thing, but you get to use the arrow keys in Illy to adjust the number of sides on the fly, which is faster. In ID using the arrow keys "gridifys" the darn thing.

As far as the math, I didn't look too hard at your equation, but why bother? ID will do it for you, and more accurately. It's been too lang since I took geometry, but I think the number you want is (sin 60 degrees)*length of your side. Sine of 60 degrees, to 5 places, is 0.86603, or pretty much what Jeffrey said.

• ###### 10. Re: Best way to make triangle?

Essentially the same thing, but you get to use the arrow keys in Illy to adjust the number of sides on the fly, which is faster. In ID using the arrow keys "gridifys" the darn thing.

http://indesignsecrets.com/cs5s-gridified-tools-adds-a-wrinkle-to-drawing-starbursts-and-p olygons.php

Bob

• ###### 11. Re: Best way to make triangle?

Funny, I probably made the same mistake you made -- (1/2a)² + b² = a² and then reversing the calculation to get b.

Lessee, one step at a time. a² + b² = c²  , with c = long edge and we want b.

So you (and I) probably first took c = 2a -- but that's not right; c is the actual initial value of a and a itself would be a/2

so

(a/2)² + b² = a²

reversing:

b² = a² - (a/2)²

simplifying to

b² = a² - a²/4

and then

b² = 0.75a², so b = Sqr(0.75a)

With a unit value for a, we get a ratio of b = 0.866025a

Message was edited by: [Jongware] (Wassup with that? Server Error while typing?)

• ###### 12. Re: Best way to make triangle?

My brain is fried this week. I'll never remember the spacebar trick (probably doesn't help that I'm not fond of gridifies tools).

@Ariel, yoru last post was blank...

• ###### 14. Re: Best way to make triangle?

Jongware, your post ends with: and...

Talk about cliffhangers!

Anyway, I don't think I made the mistake you mention. I used 1/2a where

needed. It was just bad maths: (1/2a)2 != 1/2a2

Ariel

• ###### 15. Re: Best way to make triangle?

another blank post in reponse to me before your last one to Jongware...

• ###### 17. Re: Best way to make triangle?

Ariel, Whatever you’re doing is resulting in empty posts on the forum.

I’ve seen this when replying using web mail.

Bob

• ###### 18. Re: Best way to make triangle?

sin60 and (sqr root of 3) x.5 both give the same ratio. Math IS fun as long as your not in ninth grade.

• ###### 19. Re: Best way to make triangle?

Sin 60 is also the same as cos 30.

Actually, it was 10th grade, and it WAS fun then. Not so much now, though.

• ###### 20. Re: Best way to make triangle?

Actually, it was 10th grade, and it WAS fun then.

Well, you didn't have Ms. Corcoran.

• ###### 21. Re: Best way to make triangle?

LOL

• ###### 22. Re: Best way to make triangle?

> Anyway, I don't think I made the mistake you mention.

Attempting to do it from memory also gave me 1/2 Sqrt(2). It took me half an A4 to git it right (fortunately, Math didn't care about the metric page size).

That's why I reckoned I made the same mistake.

• ###### 23. Re: Best way to make triangle?

As I said earlier, Why bother?

ID is much faster at math, and uses many more decimal places, I bet, than any of us. By the time you do the calculation you could have finished three pages of the layout.

• ###### 24. Re: Best way to make triangle?

Peter Spier wrote:

ID is much faster at math, and uses many more decimal places, I bet, than any of us.

Yeah but when working on paper I can calculate Sqrt(0.75x) and sin(60)! Despite being accurate to 15 decimal digits, my version of InDesign can't do that.

CS6, so I'm told, can finally calculate "1 + 2 + 3". A small miracle it may be and much requested the past years, but does this also allow sines and square rooting?

• ###### 25. Re: Best way to make triangle?

ID likes to hide it's math skills from human view.

• ###### 26. Re: Best way to make triangle?

Thanks all for the help. Sorry about the blank posts -- some got through, some didn't.

The triangle business has been sorted out very nicely at this stage, and my mistake was that (1/2a)^2 = 1/4a^2 NOT 1/2a^2

Ariel

PS As usual, for questions posed via email there doesn't seem to be an option to mark anything as answered.

PPS Weird forum layout. What on earth does "trending questions" mean?

• ###### 27. Re: Best way to make triangle?

What on earth does "trending questions" mean?

Apparently that's newspeak for "recent posts."

• ###### 28. Re: Best way to make triangle?

Make any shape,select it, then go to object, convert shape, triangle