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

The video tutorial explains how to solve a complex triangle problem using the sine and cosine rules. It involves calculating the areas of two triangles, ACD and ABC, and then finding the area of triangle BCD by subtracting the area of ACD from ABC. The tutorial emphasizes the importance of using the full display of the calculator for accuracy and provides a detailed step-by-step approach to solving the problem.

Which rule is necessary when there are no right angles in a triangle?

• Quadratic formula

• Pythagorean theorem

• Sine and cosine rules

• Area of a circle

What is the formula for the cosine rule?

• a^2 = b^2 + c^2 - 2bc cos A

• a/sin A = b/sin B = c/sin C

• a^2 + b^2 = c^2

• Area = 1/2 ab sin C

What is the first step in calculating the area of triangle ACD?

• Use the cosine rule

• Use the sine rule

• Find the length of AB

• Calculate the perimeter

Which rule is used to find the length CD in triangle ACD?

• Cosine rule

• Pythagorean theorem

• Sine rule

• Area formula

What is the calculated length of CD?

• 4.9

• 3.8

• 5.65

• 6.2

How is the angle C in triangle ACD calculated?

• Using the area formula

• Using the cosine rule

• Using the sine rule

• Using the tangent rule

What is the final calculated area of triangle ABC?

• 9.16 cm²

• 15.34 cm²

• 19.59 cm²

• 10.42 cm²

What is the final area of triangle BCD after subtraction?

• 9.16 cm²

• 19.59 cm²

• 15.34 cm²

• 10.42 cm²

How many marks are awarded for finding the value of CD?

• 4 marks

• 1 mark

• 2 marks

• 3 marks

What should you be careful about when doing calculations?

• Using a pen

• Using a ruler

• Writing in pencil

• Rounding off too early