How to Find the Angle of a Quadrilateral with an Acute Angle

The video tutorial explains how to solve a geometry problem involving a triangle. It covers the use of the cosine rule to find a side length and the sine rule to determine a missing angle. The importance of not rounding intermediate results is emphasized to ensure accuracy. The tutorial concludes with calculating the final angle and rounding it to one decimal place, along with a breakdown of how marks are allocated for each step.

Why is it important not to round off the answer until the final step?

• To avoid using a calculator

• To save time during calculations

• To make the calculations easier

• To ensure the final answer is accurate

What is the cosine rule formula used in this problem?

• a^2 = b^2 + c^2 + 2bc cos A

• a^2 = b^2 + c^2 - 2bc cos A

• a^2 = b^2 - c^2 + 2bc cos A

• a^2 = b^2 - c^2 - 2bc cos A

Which side length was calculated using the cosine rule?

• SQ

• QR

• RS

• PQ

What is the sine rule formula used to find the missing angle?

• sin A / b = sin B / a = sin C / c

• a / sin A = b / sin B = c / sin C

• sin A / a = sin B / b = sin C / c

• a / sin B = b / sin A = c / sin C

What is the value of the angle calculated using the sine rule?

• 27 degrees

• 61.58 degrees

• 120 degrees

• 91.4 degrees

How do you find the final angle in a triangle?

• Multiply all known angles

• Divide known angles by 2

• Subtract known angles from 180 degrees

• Add all known angles

What is the final angle SQR rounded to one decimal place?

• 120.0 degrees

• 61.5 degrees

• 27.0 degrees

• 91.4 degrees

Which rule is used to calculate a missing side when given two sides and the included angle?

• Tangent rule

• Pythagorean theorem

• Cosine rule

• Sine rule

What is the first step in solving the problem using the cosine rule?

• Identify the known angles

• Substitute the known values into the formula

• Calculate the missing angle

• Round off the final answer

How many marks were allocated for correctly using the sine rule?

• Three marks

• One mark

• Two marks

• Four marks