Year 9

Finding missing sides using sine and cosine for any angle

Year 9

Finding missing sides using sine and cosine for any angle

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Lesson details

Key learning points

  1. In this lesson, we will learn how to find missing sides using sine and cosine for any angle in a triangle.

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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.
Complete the statement: In a right angled triangle that has an interior angle of 30 degrees, opposite/ hypotenuse = .................
0.2
Correct answer: 0.5
0.87
Q2.
Complete the statement: In a right angled triangle that has an interior angle of 60 degrees, opposite/ hypotenuse = .................
0.2
0.5
Correct answer: 0.87
Q3.
Complete the statement: In a right angled triangle that has an interior angle of 60 degrees, adjacent/ hypotenuse = .................
0.2
Correct answer: 0.5
0.87
Q4.
Complete the statement: In a right angled triangle that has an interior angle of 30 degrees, adjacent/ hypotenuse = .................
0.2
0.5
Correct answer: 0.87
Q5.
What is the length of side a?
An image in a quiz
Correct answer: 1.5 cm
3.4 cm
6 cm
Q6.
What is the length of side b?
An image in a quiz
10 cm
Correct answer: 14 cm
3.5 cm
Q7.
What is the size of angle a?
An image in a quiz
Correct answer: 30 degrees
45 degrees
60 degrees

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 ?
An image in a quiz
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?
An image in a quiz
0.86 cm
10 cm
Correct answer: 10.6 cm
Q5.
What is the correct step for calculating the length of side a?
An image in a quiz
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