GCSE Secondary Maths Age 13-17 - Pythagoras & Trigonometry: Trigonometry - Explained

The video tutorial covers circle geometry and trigonometry. It begins with an introduction to circle geometry, explaining the given measurements and angles. The tutorial then explains why angle BCD is 90 degrees using circle theorems. It proceeds to calculate the length of BC in a right-angled triangle using trigonometry, emphasizing the importance of not rounding intermediate results to avoid errors. The tutorial concludes with a detailed application of trigonometry to solve the problem, highlighting key steps and concepts.

What is the significance of BOD being a diameter in the circle?

• It implies angle BCD is 90 degrees.

• It means BOD is the longest chord.

• It indicates the circle is a semicircle.

• It shows that BOD is a tangent.

Why is angle BCD exactly 90 degrees?

• Because BOD is a diameter.

• Because BCD is a tangent.

• Because BCD is a chord.

• Because BCD is an arc.

Which trigonometric function is used to find the radius OB?

• Secant

• Sine

• Tangent

• Cosine

What is the length of the radius OB calculated using sine?

• 2.75 cm

• 7 cm

• 4.01 cm

• 8.03 cm

Why is it important not to round off intermediate results?

• To ensure the answer is a whole number.

• To simplify the process.

• To make calculations easier.

• To avoid errors in final calculations.

Which trigonometric function is used to find the length of BC?

• Cosecant

• Tangent

• Cosine

• Sine

What is the final calculated length of BC to three significant figures?

• 7.00 cm

• 8.03 cm

• 4.01 cm

• 2.75 cm