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Unit review: angles
Textbook: Part 4, unit review, pp. 82–83
GoalReview of angles: comparing, degrees, protractor, drawing, sums.
New words
angle · burchakdegree · gradusprotractor · transportiradjacent angles · qo‘shni burchaklar
Explanation
In this unit we learned comparing angles by laying them on each other, measuring in degrees, measuring and drawing with a protractor, and that adjacent angles on a line and the angles of a triangle each add up to 180°. On a clock the minute hand turns 6° a minute and the hour hand 30° an hour.
Worked examples
At 2:00 the angle is 2 × 30° = 60°. The minute hand turns 25 × 6° = 150° in 25 minutes.
The angle adjacent to 72° is 180° − 72° = 108°.
Class activity
“Angle quiz”: two teams take turns naming a kind of angle, working out degrees or drawing an angle on the board; correct answers earn points.
Practice
1
How many degrees is the angle between the hands at 2:00?
60
2
Two angles of a triangle are 55° and 65°. How many degrees is the third?
60
3
How many degrees is the angle adjacent to a 72° angle?
108
4
How many degrees does the minute hand turn in 25 minutes?
150
5
What kind of angle is 100°?
obtuse