Additive Angles — Let's Practise!

Additive Angles — Let's Practise! exercise

• Find the combined angles.

  Hints

  In this example, to find the combined angles we must add 20 + 45.

  When adding the two angles, try adding the ones first and then the tens.

  Solution

  1. 31° + 52° = 83°
  2. 39° + 47° = 86°
  3. 47° + 71° = 118°
  4. 52° + 32° = 84°

• What is the total of the combined angles?

  Hints

  To find the total, all three angles must be added together.

  Try partitioning each number and adding the tens and ones separately.

  First add two angles together, then add the third angle onto this total.

  Solution

  26° + 52° + 32° = 110°

• What is the total of the two angles?

  Hints

  First, find the value of the two angles that must be added together.

  Angle (a) is 36° and angle (b) is 42°. Now we need to add these together to find the combined amount.

  Solution

  36° + 42° = 78°.

• What do the angles total?

  Hints

  There are three angles that we need to add together.

  Try adding the tens and ones separately. For example, first add 70 + 60 + 20.

  Solution

  75° + 60° + 24° = 159°.

  We could solve this by first adding the tens, 70 + 60 + 20 = 150, then adding the ones, 5 + 0 + 4 = 9, before combining these two answers together. 150 + 9 = 159°.

• What is the sum of the combined angles?

  Hints

  To find the combined angles, the two separate angles need to be added together.

  What is 38 + 22?

  Try adding the ones first and then the tens.

  Solution

  38° + 22° = 60°

• Find the missing angle.

  Hints

  We know that (a) + (b) + (c) = 152. What is the total of (a) + (c)?

  (a) + (c) or 35° + 78° = 113°. What do we need to do next to find angle (b)?

  152 - 113 will give the answer to the missing angle (b).

  Solution

  • (a) + (b) + (c) = 152°
  • (a) + (c) = 113°
  • 152 - 113 = 39°

  • We can check this by adding all three angles together: 35 + 39 + 78 = 152.