Year 9

Using inverse sine and cosine to find missing angles

Year 9

Using inverse sine and cosine to find missing angles

Lesson details

Key learning points

  1. In this lesson, we will use inverse sine and cosine to find missing angles in triangles.

Licence

This content is made available by Oak National Academy Limited and its partners and licensed under Oak’s terms & conditions (Collection 1), except where otherwise stated.

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7 Questions

Q1.
What is the length of side marked q ?
An image in a quiz
10 cm
Correct answer: 2.5 cm
5 cm
Q2.
What is the length of the side marked r ?
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15 cm
22 cm
Correct answer: 5.5 cm
Q3.
What is the correct step for calculating the length of side b?
An image in a quiz
Correct answer: Option 1
Option 2
Option 3
Q4.
What is the length of of b correct to 1 decimal place?
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0.86 cm
10 cm
Correct answer: 10.6 cm
Q5.
What is the correct step for calculating the length of side a?
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Option 1
Option 2
Correct answer: Option 3
Q6.
What is the length of a, correct to 1 decimal place?
An image in a quiz
0.5 cm
23 cm
Correct answer: 23.0 cm
39.2 cm
Q7.
Which ratio would you use to find the length of the missing side in the triangle below?
An image in a quiz
Correct answer: cosine
pythagoras
sine

6 Questions

Q1.
Fill in the gap: You can use the inverse sine function to work out the unknown angle, when given the opposite and ................. in a right- angled triangle.
adjacent
Correct answer: hypotenuse
symmetry
Q2.
Fill in the gap: You can use the inverse cosine function to work out the unknown angle, when given the hypotenuse and ................. in a right- angled triangle.
Correct answer: adjacent
opposite
symmetry
Q3.
Use the sine ratio to find out the missing angle in the triangle shown below.
An image in a quiz
15 degrees
Correct answer: 30 degrees
45 degrees
60 degrees
Q4.
Which is the correct method to work out the missing angle?
An image in a quiz
Correct answer: Cosine
Pythagoras
Sine
Q5.
Which is the correct method to work out the missing angle?
An image in a quiz
Cosine
Pythagoras
Correct answer: Sine
Q6.
Which is the correct method to work out the length of missing side?
An image in a quiz
Correct answer: Cosine
Pythagoras
Sine