The vertex of the angle may be on the circle, inside the circle, or outside the circle. Each type of angle has a formula for computing the measure of the intercepted arc. Think of a poem, a jingle, a song, or some other way to remember the three formulas.

Question

mathmate · Answer

This will help you remember, but it's not a poem, :(
For chords that meet internally, ADD & divide by 2
For chord that meet externally, SUBTRACT & divide by 2
For chord that meet at the circumference, well, neither add nor subtract, just divide by 2.
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It's like your wallet, when money comes IN, you add, 
when money goes OUT, you subtract!