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Common Core Math4th GradeGeometry

4.G.1: Draw and Identify Lines and Angles

Also written as 4.G.A.1 and CCSS.MATH.CONTENT.4.G.A.1 · Cluster: Draw and identify lines and angles, and classify shapes by properties of their lines and angles.

Make 4.G.1 Graph PaperAll 28 4th Grade Math Standards

The Official Wording

Draw points, lines, line segments, rays, angles (right, acute, obtuse), and perpendicular and parallel lines. Identify these in two-dimensional figures.

Common Core State Standards, Grade 4, Geometry · Read it at the source · Checked October 14, 2026

What 4.G.1 Means in Plain English

Fourth graders learn the vocabulary of geometry by drawing it: a point, a line with an arrow on each end, a segment that stops at two endpoints, a ray with one endpoint and one arrow. Then they find these parts in shapes, like a rectangle’s two pairs of parallel sides.

Third grade sorted shapes by their sides and square corners (3.G.1). These words become sorting rules in 4.G.2 and get measured in degrees in 4.MD.5. In 5th grade, parallel sides and right angles decide where each quadrilateral sits in the family tree (5.G.4).

4.G.1 I Can Statements

  • I can draw a point, line, segment and ray and label each one.
  • I can tell right, acute and obtuse angles apart with a square corner.
  • I can find parallel and perpendicular sides inside a shape.

4.G.1 Worked Example

A house drawn on grid paper, then taken apart into the segments, sides and angles the standard names.

Problem

On grid paper, draw a house: a square for the walls and a steep pointed roof. Label the corners A to E, starting at the bottom left and going around. Name the segments, the parallel and perpendicular sides, and the kind of angle at each corner.

Taking a house apart into lines and angles
  1. Each side stops at two corners, so each side is a line segment, and each corner is a point.Segments AB, BC, CD, DE and EA
  2. The two walls run straight up. Drawn as long as you like, they would never meet.Wall EA is parallel to wall BC
  3. The floor meets each wall in a square corner, so the floor is perpendicular to both walls.Right angles at A and B
  4. Hold the corner of an index card at C and at E. The roof opens wider than the card.Obtuse angles at C and E
  5. A steep roof makes the peak narrower than the card’s corner.Acute angle at D
  6. Extend the floor past B with an arrow and it becomes a ray. Add an arrow past A too and it is a line.Ray AB, then line AB
AnswerFive segments. Walls EA and BC are parallel, and the floor AB is perpendicular to both. Right angles at A and B, obtuse angles at C and E, and an acute angle at D.

Check it: Five corners and five angles named: two right, two obtuse and one acute. Every corner of the house has exactly one.

Common Mistakes with 4.G.1

Calling every straight mark a line

A side of a triangle, with two endpoints, named “line AB”

Try this: Check the ends before naming: two endpoints make a segment, one endpoint and one arrow a ray, two arrows a line.

Judging an angle by its arms

A right angle with long arms called bigger than an obtuse angle with short ones

Try this: Compare only the opening between the arms, using an index card corner. Longer arms never make an angle any bigger.

Perpendicular only when upright

The sides of a tilted square not called perpendicular because neither one stands straight up

Try this: Turn the paper until one side lies flat. If the other side now stands straight up, the two sides are perpendicular.

Where 4.G.1 Fits

Comes Before3.G.1Sort quadrilaterals by shared attributes such as four equal sides or four right angles.2.G.1Recognize and draw shapes with a given number of sides or angles.
Alongside4.MD.5Understand angles as turns measured in degrees.4.G.2Sort shapes by parallel or perpendicular sides and by the size of their angles.
Comes Next5.G.4Classify two-dimensional figures in a hierarchy based on their properties.8.G.5Work out which angles match when a line crosses two parallel lines.

Practice 4.G.1

Graph Paper GeneratorFree ToolCorners on grid points make the drawing honest: sides along grid lines are parallel or perpendicular at a glance, and a diagonal roof gives acute and obtuse angles to name.Large squaresLetterPrint
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Math Worksheet GeneratorFree ToolGeometry practice at the 4th grade level with an answer key: name segments, rays and lines, and label each angle right, acute or obtuse.Grade 4ShapesAnswer key
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Quick Check

  1. What is the difference between a ray and a line segment?
  2. How many right angles does a capital H have?
  3. An angle opens wider than the corner of a sheet of paper. What kind of angle is it?

4.G.1: Other Names

4.G.14.G.A.1CCSS.MATH.CONTENT.4.G.A.1

Common Core State Standards © Copyright 2010. National Governors Association Center for Best Practices and Council of Chief State School Officers. All rights reserved. Official wording from the Common Core State Standards PDFs at corestandards.org, last checked October 14, 2026. The explanation, I can statements, example, mistakes and practice on this page are EMStudio’s own, written beside the official wording. They are not part of the standard.