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Similar Triangles Worksheet

Geometry Math · printable worksheet (PDF) with answer key · 13 problems · CCSS HSG.SRT.A.2, HSG.SRT.A.3

A printable geometry similar triangles practice worksheet with 13 problems and a complete, step-by-step answer key — formatted to print cleanly on standard paper. Included in the one-time $20 unlock for the full NudgeLearn library.

Sample problems

Two triangles are similar when their matching angles are equal and their matching sides are proportional. By the Angle-Angle (AA) shortcut, two pairs of equal angles are enough to prove similarity. Once triangles are similar, set up a proportion of matching sides to find a missing length. Keep answers exact.

1. Two triangles each have angles measuring $3 5^{\circ}$ and $7 0^{\circ}$ . Must the triangles be similar? Explain in one sentence.
2. Triangle $A B C$ has angles $9 0^{\circ}$ and $4 0^{\circ}$ . Triangle $D E F$ has angles $9 0^{\circ}$ and $5 0^{\circ}$ . Are the triangles similar? Explain.
3. Two similar triangles have matching sides of $5$ and $15$ . What is the scale factor from the smaller triangle to the larger one?
4. The two triangles are similar. Find the scale factor from the smaller triangle to the larger one.

Plus 9 more problems and a full answer key in the PDF.

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