Draw points, lines, line segments, rays, angles (right, acute, obtuse), and perpendicular and parallel lines. Identify these in two-dimensional figures.
Official wording from the Common Core State Standards for Mathematics (© 2010 National Governors Association Center for Best Practices and Council of Chief State School Officers). View on thecorestandards.org
Geometry has its own vocabulary, and fourth grade is where students learn the basic building blocks precisely. A point marks an exact location. A line goes on forever in both directions, a line segment has two endpoints, and a ray has one endpoint and continues forever in one direction. Two rays that share an endpoint form an angle, which can be right (a square corner, exactly 90°), acute (smaller than a right angle) or obtuse (larger than a right angle but less than a straight line).
Students also learn two important relationships between lines. Parallel lines run in the same direction and never meet, like the rails of a train track. Perpendicular lines meet at a right angle, like the corner of a sheet of paper. The standard asks students to draw each of these objects with a ruler and to find them inside two-dimensional figures, such as spotting the parallel sides of a trapezoid or the perpendicular sides of a rectangle. Precise drawing and correct naming lay the groundwork for classifying shapes in 4.G.A.2.
Students draw a segment and call it a line. Emphasize the arrowheads: two arrows for a line, one for a ray, and endpoints with no arrows for a segment.
Students may only recognize parallel lines drawn side to side. Show tilted and vertical parallel pairs so direction, not orientation, is the key.
Lines that cross at a slant are intersecting but not perpendicular. A right angle must be formed, which students can check with the corner of an index card.
A right angle rotated so its corner points up is still a right angle. Test every angle against a square corner rather than its position on the page.
Look at a rectangle ABCD. Name a pair of parallel sides, a pair of perpendicular sides, and the type of angle at each corner.
Answer: AB is parallel to DC, AB is perpendicular to BC, and all four corners are right angles, which together make 4 × 90 = 360 degrees.
Hunt for examples around the classroom: the edges of a door (perpendicular), the lines on notebook paper (parallel), the hands of a clock at 2:00 (acute). Then have students draw each item carefully with a ruler and label it with correct notation.
Assessment items often show a figure and ask students to identify, say, all the obtuse angles or which segments are parallel. Practicing with irregular figures, not just squares, prepares students for these.
Original questions written for this standard. Choose an option or type your answer, then press Check. Every question has a worked explanation.
Answer: D) A ray
A ray starts at one endpoint and continues forever in one direction.
Answer: A) Perpendicular lines
Perpendicular lines meet at a right angle. Other intersecting lines may meet at any angle.
Answer: B) Obtuse
130° is larger than a right angle (90°) but less than a straight line (180°), so it is obtuse.
Answer: 2 (also accepted: two)
A line segment is part of a line between two endpoints.
Answer: D) The rails of a straight train track
Train rails run in the same direction and never meet, so they are parallel. A clock at 3:00 shows perpendicular hands.
Answer: 4 (also accepted: four)
Every corner of a square is a right angle, and a square has 4 corners.
Recognize and draw shapes having specified attributes, such as a given number of angles or a given number of equal faces. Identify triangles, quadrilaterals, pentagons, hexagons, and cubes.
A full lesson with slides, activities and an exit ticket on points, lines, rays and angles, pitched to grade 4 and editable in PowerPoint or Google Slides.
Make a lesson →A printable, differentiated worksheet on 4.G.A.1 with an answer key, ready in about a minute.
Make a worksheet →Turn points, lines, rays and angles into a quiz students answer online that marks itself, with a class summary for you.
Build a test →A line extends forever in both directions and is drawn with two arrowheads. A line segment is a part of a line with two endpoints.
No. Perpendicular lines are a special kind of intersecting lines that meet at a right angle.