GCSE Secondary Maths Age 13-17 - Shapes & Area: Similar Shapes - Explained

The video tutorial explains how to solve problems involving similar triangles by finding the scale factor. It demonstrates calculating the scale factor by comparing corresponding sides of similar triangles and using it to determine unknown side lengths. The tutorial provides solutions for two parts: finding the length of DF and CB, emphasizing the importance of understanding the concept of similar triangles and scale factors in geometry.

What is the first step when you encounter a problem involving similar triangles?

• Calculate the area of the triangles

• Find the scale factor

• Measure the angles

• Determine the perimeter

If the side AB of triangle ABC is 8.4 cm and the corresponding side DE of triangle DEF is 12.6 cm, what is the scale factor?

• 2.0

• 1.5

• 0.8

• 1.2

How do you calculate the length of DF if AC is 6.4 cm and the scale factor is 1.5?

• Add 1.5 to 6.4

• Divide 6.4 by 1.5

• Subtract 1.5 from 6.4

• Multiply 6.4 by 1.5

What is the length of CB if FE is 15 cm and you need to scale down by a factor of 1.5?

• 9 cm

• 12 cm

• 15 cm

• 10 cm

When scaling from a larger triangle to a smaller triangle, what operation is performed with the scale factor?

• Add the scale factor

• Subtract the scale factor

• Divide by the scale factor

• Multiply by the scale factor