Angles and the protractor: printable worksheets
Classify angles, estimate their size, and measure and draw them with a true-size protractor. Find unknown angles by adding and subtracting, and write turns as degrees.
Sample worksheet
The first 3 problems of a real worksheet, made the way the builder makes it. Open it in the builder to change the number of problems, the difficulty and the layout, then print.
1.
Is the angle acute, right, obtuse or straight?
- acute
- right
- obtuse
- straight
2.
Estimate. Which is closest to the measure of the angle?
- A.30°
- B.60°
- C.90°
- D.120°
3.
Use the protractor. What is the measure of the angle?
Measure: °
Show answers
1.obtuse
2.90°
3.70°
What students practise
I can measure and draw angles with a protractor and tell acute, right and obtuse angles apart.
Students understand an angle as a turn measured in degrees, measure and draw angles with a protractor by reading the scale that starts at zero on the baseline ray, and add or subtract to find unknown angles.
Key words
- angle
- two rays that share an endpoint
- degree
- a unit that measures a turn; a full turn is 360 of them
- protractor
- a tool that measures and draws angles
- acute
- smaller than a right angle
- obtuse
- greater than a right angle and less than a straight angle
- baseline
- the line along the bottom of the protractor
Common mistakes
- Reads the wrong scale and writes the supplement of the angle, such as 115 instead of 65.
- Judges the size of an angle by how long the rays are.
Standards
Common Core State Standards this worksheet practises.
- 4.MD.C.5a: Recognize angles as geometric shapes that are formed wherever two rays share a common endpoint, and understand concepts of angle measurement: an angle is measured with reference to a circle with its center at the common endpoint of the rays, by considering the fraction of the circular arc between the points where the two rays intersect the circle. (unverified)
- 4.MD.C.5b: An angle that turns through n one-degree angles is said to have an angle measure of n degrees. (unverified)
- 4.MD.C.6: Measure angles in whole-number degrees using a protractor. Sketch angles of specified measure. (unverified)
- 4.MD.C.7: Recognize angle measure as additive. When an angle is decomposed into non-overlapping parts, the angle measure of the whole is the sum of the angle measures of the parts. Solve addition and subtraction problems to find unknown angles on a diagram in real world and mathematical problems. (unverified)
- 4.G.A.1: Draw points, lines, line segments, rays, angles (right, acute, obtuse), and perpendicular and parallel lines. Identify these in two-dimensional figures. (unverified)
Related topics
- Before this: Perimeter and area (Grade 4)