Worked Example 1
Classify an Angle
An angle measures 135°. What kind of angle is it?
- 1135° is more than 90°.
- 2135° is less than 180°.
Answer: Obtuse
Florida Grade 4 Math · Geometric Reasoning
MA.4.GR.1.1: Types of Angles
What this Grade 4 benchmark means, worked examples, common mistakes, and a free printable worksheet.
Created by a Florida mom · Published by Tropical Learning LLC
What Is Benchmark MA.4.GR.1.1?
Students explore angles in shapes and in the real world, and classify them as acute, right, obtuse, straight, or reflex, using 90° and 180° as benchmarks.
Acute: less than 90°. Right: exactly 90°. Obtuse: more than 90° but less than 180°. Straight: exactly 180°. Reflex: more than 180° but less than 360°.
Official benchmarkInformally explore angles as an attribute of two-dimensional figures. Identify and classify angles as acute, right, obtuse, straight or reflex.
On the FAST test: part of the Grade 4 reporting category Geometric Reasoning, Measurement, and Data Analysis and Probability, which is about 31–37% of the test.
Worked Examples
Worked Example 2
Angles on a Clock
At 3:00, what kind of angle do the hands of a clock make?
- 1The hands point to 12 and 3.
- 2That is a quarter of a full turn, which is 90°.
Answer: A right angle
Common Mistakes to Watch For
Judging an angle by the length of its sides
Wrong:An angle with long sides is bigger than one with short sides.
Angle size is the amount of turn between the sides, not how long the sides are.
Calling a straight angle obtuse
Wrong:A 180° angle is obtuse.
An angle of exactly 180° is a straight angle. Obtuse angles are less than 180°.
Helpful Math Tip
Use the corner of a sheet of paper as a right-angle tester: smaller than the corner is acute, bigger is obtuse.
Related Grade 4 Skills
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Start Practicing FreeIndependent Educational Platform. FastChomp is published by Tropical Learning LLC and is not affiliated with, sponsored by, or endorsed by the Florida Department of Education. FAST and Star assessment names are referenced for informational purposes only. FastChomp practice questions are original educational materials, not official Florida FAST assessment questions.