# Unit 11 Section 1 : Angle Measures

In this section we review measuring angles, and the different types of angles.

The box below shows the different types of angles you can have.

## Example Question

Measure the angle in the diagram shown below.
 To measure this angle, you must first place a protractor over the angle, with the centre of the protractor over the point of the angle. Click on the angle once to see a protractor appear. Look how the bottom line lines up with the zero on the protractor scale. You need to follow the scale round and read the angle where the other line crosses the scale. Make sure you always read the scale starting from zero. You can hide the protractor again by clicking it once.
We can see that the angle is 47°. It is an acute angle.

## Practice Question

Work out whether each of the angles below is acute, obtuse or reflex, then click on the button marked to see whether you are correct.
 A   B   C   D   E

## Exercises

Work out the answers to the questions below and fill in the boxes. Click on the button to find out whether you have answered correctly. If you are right then will appear and you should move on to the next question. If appears then your answer is wrong. Click on to clear your original answer and have another go. If you can't work out the right answer then click on to see the answer.

In the two questions below, it may be difficult to measure the angles on your screen with a protractor. The questions are the same as those on pages 190 and 191 in the 8A practice book, so you could measure the angles on the printed page and type their values on the screen.

Question 1
Measure the acute angles below.
 Enter the angles here: (a) °   (b) °   (c) °   (d) °
Question 2
Measure these angles.
 (a) °   (b) °   (c) °   (d) °   (e) °   (f) °
Question 3
State whether each of the following angles is acute, obtuse or reflex.
 (a) Acute Obtuse Reflex    (b) Acute Obtuse Reflex    (c) Acute Obtuse Reflex    (d) Acute Obtuse Reflex    (e) Acute Obtuse Reflex    (f) Acute Obtuse Reflex
Question 4
On a piece of paper, draw a triangle, and measure the three internal angles accurately.

(a) Write the three angles in these boxes:
°      °      °

°

Question 5
On a piece of paper, draw a quadrilateral (four-sided polygon), and measure the four internal angles accurately.

(a) Write the four angles in these boxes:
°      °      °      °

°

Question 6
On a piece of paper, draw a point and mark three lines coming off it.
It will be similar to the diagram below, but does not need to be identical. Measure the three angles around the point accurately.

(a) Write the three angles in these boxes:
°      °      °

°

Question 7
On a piece of paper, draw a straight line and mark a point on it.
Then draw a straight line from the point away from the line.
It will be similar to the diagram below, but does not need to be identical. Measure the two angles on the straight line accurately.

(a) Write the two angles in these boxes:
°      °