Cosine Rule and Triangle Properties

The video tutorial explains how to solve a triangle problem using the cosine rule. It begins by introducing the problem and the need for the cosine rule. The instructor then sets up the equation, explaining each step in detail. The solution is calculated, and the result is verified to ensure it is reasonable. The tutorial concludes with a summary of the process and the importance of verifying the solution.

What type of triangle is being discussed in the problem?

• Scalene triangle

• Right-angled triangle

• Equilateral triangle

• Isosceles triangle

Which mathematical rule is chosen to solve the problem?

• Tangent rule

• Cosine rule

• Sine rule

• Pythagorean theorem

What is the main challenge in remembering the cosine rule?

• The use of angles

• The need for a calculator

• The extra term at the end

• The order of operations

What is the first step in applying the cosine rule?

• Square the two known sides

• Identify the longest side

• Multiply the sides

• Find the angle

What operation is performed after squaring the sides in the cosine rule?

• Addition

• Subtraction

• Multiplication

• Division

Why is the initial result of 106 considered incorrect?

• It is not a whole number

• It is the square of the length

• It is too small

• It is a negative number

What is the final step to find the length of the side?

• Divide by the angle

• Multiply by two

• Take the square root

• Add the angles

What is the approximate length of the side to one decimal place?

• 12.0

• 10.3

• 9.8

• 11.5

Why is it important to check the reasonableness of the result?

• To ensure it is a whole number

• To confirm it matches the angle

• To verify it fits the triangle's dimensions

• To make sure it is a prime number

What tool is necessary to complete the calculations?

• Ruler

• Protractor

• Compass

• Calculator