Free printable worksheets with answer keys. Pick a level, preview the questions, then open the sheet to swap or delete any single question.
Easy: SSS, SAS and ASA
Two triangles are congruent when three pairs of parts fit one of the rules. SSS is three sides; SAS is two sides and the angle between them; ASA is two angles and the side between them; AAS is two angles and a side that is not between them; HL is the hypotenuse and a leg of two right triangles. Two sides with an angle that is not between them (SSA), and three angles (AAA), are not enough.
Which rule proves that triangle ABC is congruent to triangle DEF: SSS, SAS, ASA, AAS or HL? If none does, write “not enough information”.
Tip: tick “Step-by-step answer key” in the generator to print each step for marking.
AAA only fixes the shape, not the size, so it gives similar triangles. SSA can fit two different triangles, because the unknown side can swing to two positions.
HL is a special case of SSA where the angle is a right angle. In a right triangle, the Pythagorean theorem fixes the third side, so only one triangle is possible.
Yes. Numbers are generated each time, and the answer key is calculated for that sheet. Swap any single question and its answer updates too.
Yes. In the generator, add more skills; each gets its own section on the sheet with its own instructions.
Yes. Generating and printing from the browser is free with no sign-up. PDF downloads need a free account.