GCSE Secondary Maths Age 13-17 - Geometry & Measures: Arc length - Explained

The video tutorial explains how to calculate the length of an arc in a circle sector with a radius of 7 and an angle of 40 degrees. It begins by determining the circle's circumference using the formula π multiplied by the diameter. The tutorial then focuses on finding the arc length by multiplying the fraction of the circle's angle (40/360) by the total circumference. The final answer is rounded to three significant figures, resulting in 4.89 cm. The video also discusses the allocation of marks for the calculation steps and emphasizes understanding the process for solving similar problems.

What is the first step in solving the problem of finding the arc length in a circle sector?

• Measure the angle of the sector

• Find the circumference of the entire circle

• Calculate the area of the sector

• Determine the diameter of the circle

Which formula is used to calculate the circumference of a circle?

• π multiplied by the diameter

• Both b and c

• 2π multiplied by the radius

• π multiplied by the radius

How is the arc length calculated once the circumference is known?

• By dividing the circumference by the fraction of the angle over 360

• By multiplying the circumference by the fraction of the angle over 360

• By dividing the circumference by the angle in degrees

• By multiplying the circumference by the angle in degrees

What is the final answer for the arc length rounded to three significant figures?

• 4.88 cm

• 4.89 cm

• 4.90 cm

• 4.87 cm

What is emphasized as important to understand in the final section?

• How to calculate the area of a circle

• How to find the length of an arc and the area of a sector

• How to measure angles accurately

• How to use a calculator for complex calculations