Vocab
What do we call an angle that is exactly 90°?
Right angle
Is 145° acute, obtuse, or reflex?
obtuse
Angles on a straight line. One angle is 130°. What is the missing angle?
50°
If x + 30 = 180, what is x?
x = 150
What is the mean of 4, 8, 6, and 10?
7
What do we call the line from the centre point of a circle to its edge?
radius
What is the sum of angles in any triangle?
180°
Angles around a point. Three angles are 90°, 120°, and 75°. What is the fourth?
75°
Two vertically opposite angles are labelled 3y and 75°. What is y?
y = 25
A pie chart has 4 equal sections. What angle does each section represent?
90°
Which tool is used for drawing angles?
protractor
An angle is three times the size of a right angle. What type of angle is it?
Reflex (270°)
Two lines cross. One angle is 67°. What are the other three angles?
113°, 67°, 113°
Angles on a straight line: 2x + 40 and x + 20. What is x? What are the angles?
3x + 60 = 180, x = 40. Angles are 120° and 60°
The mean of five numbers is 12. Four of the numbers are 10, 14, 9, and 13. What is the fifth number?
Total = 60. 60 − 46 = 14
What is it called when two lines meet at 90 degrees?
perpendicular
An isosceles triangle has a top angle of 40°. What are the two base angles?
70° each
Angles around a point include these four: 90°, 75°, 110°, and angle k. What is k?
360 − 90 − 75 − 110 = 85°
A triangle has angles x, 2x, and 3x. What is x? What are the three angles?
6x = 180, x = 30. Angles are 30°, 60°, 90°
A bar chart shows the following values: 15, 22, 18, 25, 10. What is the mean? Round to one decimal place.
90 ÷ 5 = 18
What do we call the corner point of rays. The place two lines meet.
vertex
A triangle has angles in the ratio 1:2:3. What are the three angles? What type of triangle is it?
30°, 60°, 90° — right-angled triangle
An irregular hexagon has five angles of 110°, 125°, 100°, 130°, and 115°. What is the sixth angle?
Sum of hexagon = 720°. 720 − 580 = 140°
Angle a and angle b are vertically opposite. Angle a = 4x + 10 and angle b = 6x − 20. Find x and both angles.
4x + 10 = 6x − 20, 2x = 30, x = 15. Both angles = 70°
The mean of six numbers is 15. A seventh number is added and the new mean is 16. What is the seventh number?
Old total = 90. New total = 112. Seventh number = 22