GR4_Ch.11_Angles

Angles

Chapter 11 Review

5 minutes on a clock is 1/12 as a fraction.

Clockwise

vs.

Counterclockwise

Multiple Choice

Which clock shows 1/2 turn clockwise?

5 minutes on a clock is also 30° because...

5 minutes = 1/12 and... 

 $\frac{1}{12}\times\frac{30}{30}=\frac{30}{360}$  

Multiple Choice

What is the measure of the angle in degrees if the fraction is 3/12?

• 30°

• 60°

• 90°

• 3°

Types of Angles

Acute

Obtuse

Right

Straight

Multiple Select

Mark all the angles that are obtuse angles.

• 34°

• 91°

• 179°

• 90°

Forming Straight Angles

Angles on a straight angle sum to 180°.

Multiple Choice

62° + ___ = a straight angle

• 55°

• 148°

• 18°

• 118°

Missing Angle Measure

180° - 45° = a

a = 135°

Multiple Choice

What is the measure of angle b?

• 90°

• 66°

• 72°

• 180°

Cutting up fractions

 $\frac{1}{2}$  divided into 3 parts
Think... half the circle dividing the 5 minute increments equally 3 ways is 10 minutes or 2/12.
 $\frac{2\times30}{12\times30}=\frac{60}{360}$  so 60°.

Or...  $\frac{1}{2}$  is 180° and  $180\degree\div3=60\degree$  

Multiple Choice

 $\frac{1}{4}$  of a circle divided 3 ways equally is what in degrees?

• 30°

• 60°

• 90°

• 180°

Angles as Fractions

 $x\degree$  is  $\frac{x}{360}$  

Multiple Choice

An angle measures 35°. Through what fraction of a circle does it turn?

• $\frac{1}{3}$

• $\frac{2}{12}$

• $\frac{35}{360}$

• $\frac{7}{35}$