Using inverse sine and cosine to find missing angles

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

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7 Questions

Q1.
What is the length of side marked q ?
10 cm
Correct answer: 2.5 cm
5 cm
Q2.
What is the length of the side marked r ?
15 cm
22 cm
Correct answer: 5.5 cm
Q3.
What is the correct step for calculating the length of side b?
Correct answer: Option 1
Option 2
Option 3
Q4.
What is the length of of b correct to 1 decimal place?
0.86 cm
10 cm
Correct answer: 10.6 cm
Q5.
What is the correct step for calculating the length of side a?
Option 1
Option 2
Correct answer: Option 3
Q6.
What is the length of a, correct to 1 decimal place?
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?
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.
15 degrees
Correct answer: 30 degrees
45 degrees
60 degrees
Q4.
Which is the correct method to work out the missing angle?
Correct answer: Cosine
Pythagoras
Sine
Q5.
Which is the correct method to work out the missing angle?
Cosine
Pythagoras
Correct answer: Sine
Q6.
Which is the correct method to work out the length of missing side?
Correct answer: Cosine
Pythagoras
Sine

Lesson appears in

UnitMaths / Surds and trigonometry