Geometry
Supplementary angles worksheets
Find one missing angle in 6, 8 or 10 supplementary pairs using whole numbers, tenths or hundredths. Each numbered straight-line diagram identifies the given and unknown regions clearly.
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Vertical angles worksheets
Use two adjacent givens in 6 or 8 intersecting-line diagrams to find both opposite unknowns. Four numbered regions, whole-number or decimal precision and a two-mark answer key make every equality explicit.
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Use vertical angles and straight lines to find the two missing measures. Opposite regions are equal and adjacent regions total 180 degrees. Diagrams are not to scale.
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Customize this worksheetUse exact angle relationships to deduce each blank
Each numbered region connects the diagram to one printed measure or blank. Complementary regions total 90 degrees, supplementary regions on a straight line total 180 degrees, and opposite vertical regions are equal.
The diagrams preserve those relationships but are not drawn to the stated values. Use subtraction or vertical-angle equality, then check the result against the 90-degree or 180-degree total instead of measuring the picture.
Learning objective
What this activity builds
Apply equality of opposite vertical angles and the 180-degree total of adjacent angles to determine two missing region measures.
Worked example
Adjacent Regions 1 and 2 are 68 and 112 degrees. What are Regions 3 and 4?
Region 3 is 68 degrees and Region 4 is 112 degrees.
Opposite regions formed by the same two intersecting lines are vertical angles. Region 3 is opposite Region 1, and Region 4 is opposite Region 2, so each repeats its opposite given.
Teaching notes
Make the practice count
- Pair opposite region numbers before doing any arithmetic.
- Use the adjacent givens to check the straight-line total of 180 degrees.
- Award one mark for each unknown region so both vertical equalities are checked.
- Rotate the page or diagram to show that opposite relationships do not depend on orientation.
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