Geometry Worksheets

Free printable geometry worksheets: angle classification, missing angles, complementary and supplementary pairs, triangles and polygons. With an answer key.

A mixed sheet drawing on all five question types: classifying an angle from its measure, finding a missing angle in a triangle or on a straight line, complementary and supplementary pairs, naming a triangle from its side lengths, and naming a polygon from its side count.

Every figure is described in words rather than drawn — “two angles of a triangle measure 85° and 10°” — so the arithmetic is the whole of the question. That is deliberate: a drawn triangle labelled 85° and 10° adds nothing except a chance for the picture to disagree with its labels, and there is no “measure this with a protractor” question because a printed protractor is only correct if the page prints at exactly 100%.

What this worksheet covers

Classify angles and triangles
Find missing angles using angle facts

Common Core standards

4.G.A.1 Draw and identify points, lines, rays and angles, including right, acute and obtuse angles.
7.G.B.5 Use facts about supplementary, complementary and adjacent angles to find an unknown angle.

Sample page from Geometry Worksheets — A sample page. Every sheet is generated fresh, so yours will have different problems.

Frequently asked questions

What geometry does this cover?

The arithmetic of angles and the naming of shapes: acute, right, obtuse and straight angles; the angle sum of a triangle; angles on a straight line and around a point; complementary and supplementary pairs; classifying triangles by their sides; and polygon names from triangle to decagon.

Why are there no diagrams?

Because these questions do not need one. Every figure is given in words, and the skill being practised is the arithmetic. Questions that genuinely need a picture — vertical angles at crossed lines, for instance — are left out rather than faked with a diagram that might not print to scale.

Can I make the numbers friendlier?

Yes. Under Advanced options, “Angles are multiples of” sets how round every angle is. At 10° you get 180 − 130; at 1° you get 180 − 137. It does not affect the triangle side lengths, which are not angles.

What grade is this?

Fourth grade meets angle types and adding angles (4.MD.C.7), seventh grade does complementary and supplementary pairs (7.G.B.5), and eighth grade uses angle sums (8.G.A.5). Polygon naming and triangle classification start earlier, around third and fourth grade.