Triangle Congruence Prover

Enter the parts you know for △ABC and △DEF (matching A↔D, B↔E, C↔F). Side a = BC / EF, b = CA / FD, c = AB / DE. Leave unknowns blank.

Try an example

#	Statement	Reason

Pick a method and watch the order in which the parts must be taken. Each number is a step; the same step is marked on both triangles.

Fix ∠A, side b (AC) and side a (BC, opposite ∠A). Side a swings like a pendulum from C; wherever it lands on the base gives a valid triangle.

∠A

b = AC

a = BC