Apply angle relationships at intersections and with parallel lines cut by a transversal, including vertical, corresponding, alternate, and same-side interior angles, linear pairs, perpendicular lines, and simple equations for unknown measures. Use triangle and quadrilateral properties, including angle sums, exterior-angle relationships, side and diagonal relationships, and specialized properties of rectangles, rhombi, squares, parallelograms, and isosceles trapezoids. Apply interior- and exterior-angle sums to convex polygons, find angles of regular polygons, and justify unknown-angle solutions from marked diagrams using symbolic and written geometric reasoning rather than visual appearance.
On this page:
- Master skills like “Determine exterior angles of regular polygons”, “Determine interior angles of regular polygons”, and “Determine unknown angles in geometric diagrams” with unlimited, free practice problems
- Download (or modify) free worksheets on Geometry you can use at home or in class with practice problems across all skills in this group including “Apply angle relationships formed by intersecting lines”, “Apply the exterior angle-sum relationship for polygons”, “Apply the interior angle-sum relationship for polygons”.
- Start working on adaptive units like “Geometry - Isosceles and Equilateral Triangles” or “Geometry Problem Solving with 2D Polygons - Intro” that include these skills and will introduce and scaffold the skills carefully for maximum learning.
Geometry: Individual Skills
Master 10 individual skills with free practice problems. Mouseover to see the skill's practice problems. Create a free account to track your progress.
Your results
- Apply angle relationships formed by intersecting lines
- Apply angle relationships formed by parallel lines and a transversal
- Apply properties of quadrilaterals to determine unknown measures
- Apply properties of triangles to determine unknown measures
- Apply the exterior angle-sum relationship for polygons
- Apply the interior angle-sum relationship for polygons
- Determine exterior angles of regular polygons
- Determine interior angles of regular polygons
- Determine unknown angles in geometric diagrams
- Use geometric reasoning to justify angle relationships
Practice 'Apply angle relationships formed by intersecting lines'
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Download/Modify Free Grade 9 'Geometry' Worksheet
Print this free 'Geometry' worksheet to practice these skills away from the computer. Click 'Modify' to easily customize this worksheet to your exact needs.
This Worksheet Includes:
- Apply angle relationships formed by intersecting lines
- Apply angle relationships formed by parallel lines and a transversal
- Apply properties of quadrilaterals to determine unknown measures
- Apply properties of triangles to determine unknown measures
- Apply the exterior angle-sum relationship for polygons
- Apply the interior angle-sum relationship for polygons
- Determine exterior angles of regular polygons
- Determine interior angles of regular polygons
Units Teaching These Skills
These adaptive units introduce, teach, or reinforce skills in this group (Geometry) through scaffolded problems that grow in difficulty as concepts are understood.