It's an equilateral triangle so all sides must be the same length, it is one of the basic rules of geometry.

so you get

I don't get how you're using the product rule. Can you explain how you're using line BC to get line YZ? Surely there is another line you're using.

**I was reading up on similar triangles and thought I found a good example, however after the event, "as always" I found that the similar traingles I was using were not equilateral, where after working through the maths I found that the sides in that example AC and AB were not equal, therefore a different method had been used, which was no good for my example.** **edit: If I'm understanding correctly you've done using your carried forward error in .** **If you do **
True, hence my confusion earlier

I shall use the cos rule to show YZ = 2.

AZ = AY = 2 - we are told this. We also know angle A is 60 degrees as it's a property of equilateral triangles.

. In this example

**c = YZ** - the side we want to know,

**a = AZ = 2**,

**b = AY = 2** and

**C = A = 60 degrees** (angle A)

and so

Thus YZ is 2 units across. It has been established that BC = 3 and so the ratio of YZ to BC is 2:3

Similarly the ratio of BC to YZ is the reciprocal which is 3:2