GCSE Secondary Maths Age 13-17 - Pythagoras & Trigonometry: Trigonometry - Sin, Cos, Tan - Explained

The video tutorial explains how to solve a geometry problem involving a right angle triangle. It covers finding the angle ABC using trigonometry, specifically the cosine function. The process includes labeling the triangle, using the cosine formula, and calculating the angle with a calculator. The tutorial also discusses the effect of reducing the length of side AB on the cosine of angle ABC, emphasizing the importance of understanding the question requirements.

What is the length of side BC in the given triangle?

• 9 cm

• 7 cm

• 5 cm

• 11 cm

Which trigonometric ratio is used when you know the adjacent and hypotenuse?

• Cosine

• Sine

• Tangent

• Secant

What is the first step in solving for an angle using trigonometry?

• Label the triangle

• Choose a trigonometric ratio

• Calculate the angle

• Write down SOHCAHTOA

How do you find the angle X using the cosine ratio?

• Use the secant function

• Use the inverse cosine function

• Use the tangent function

• Use the sine function

What is the rounded value of angle X to one decimal place?

• 50.5

• 50.4

• 50.7

• 50.6

What happens to the cosine of angle ABC when the hypotenuse is shortened?

• It increases

• It decreases

• It remains the same

• It becomes zero

If the hypotenuse is reduced, what happens to the angle itself?

• It remains the same

• It becomes 90 degrees

• It decreases

• It increases