Illustrative Mathematics K–5 · Grade 4 · Unit 7 · Angles and Angle Measurement
Welcome to the arcade! Spot lines, rays, and segments, aim light beams, spin the clock tower, read the protractor panel, and sort angles. Then go for the High Score. Each station matches lessons from class.
Each station deals 8 fresh problems (High Score deals 10). A right answer on the first try earns 10 points. After a wrong answer, the game names the likely mistake and gives one more try for 5 points. At High Score, each right answer lights one of 10 lights on the scoreboard.
Hints point to what to look for: the arrows on a figure, a right-angle mark, the shaded turn on a clock, and which scale of the protractor starts at 0 on the angle’s first ray. A used hint caps that problem at 5 points.
Mixing up lines, rays, and segments, starting a ray’s name at the wrong point, calling crossing lines perpendicular, using 10° for a minute instead of 6°, reading the wrong scale of a protractor (180 minus the angle), and subtracting from the wrong whole (90°, 180°, or 360°).
Angles are in whole degrees, and in fives on the protractor. The protractor’s inner scale counts from 0 on the right and its outer scale from 0 on the left.
Each station matches a chapter of the Learn page for this unit, which walks through the ideas step by step.
Guess the Figure (Lesson 16) is an optional lesson, so there is no station for it.