The dimensions of an object or shape are the lengths of its sides and edges

A scale factor is the ratio between the dimensions of the original shape and the new shape. The scale factor can be an integer or a fraction

A regular polygon has all sides the same length and all angles equal

Similar shapes can be transformed into each other by scaling their dimensions by the same scale factor

Identify and describe the relationship between regular polygons using scale factors

Maths

In this unit pupils will describe the relationship between 2 factors using a ratio grid to calculate unknown values They will use their knowledge of multiplication and division to solve scaling problems and identify and describe the relationship between two shapes using scale factors and ratios. In the future unit pupils will link fractions to ratio and look at ratio with exchange and conversions.

 In the prior unit pupils explained why the product stayed the same when one factor is doubled and the other is halved using knowledge of equivalence. They explained the effect on the quotient when scaling the dividend and divisor by the same amount. In this unit pupils will describe the relationship between two factors and use a ratio grid to calculate unknown values. 

Ratio and proportion

The length of the sides and edges of a 2D shape

Which of these statements describe the dimensions of a 2D shape

Write the 2 words which complete this definition of a regular polygon: A regular polygon has all ___ the same length and all ___ equal. 

... the sum of the lengths of the sides of a polygon

... the ratio between the dimensions of the original shape and a new shape

... number you multiply each dimension by to create a similar polygon

Which phrase completes this sentence: A scale factor is ___.

What is the scale factor between triangles A and B?

Sam says that the scale factor between triangles A and B is 12. Are they correct?

Sam has calculated the difference between the length of a side of each triangle

Sam has not worked out how many times longer the length of a side in B is

Sam has not worked out how many 3s there are in 15

Sam has not thought about multiplication and division

Sam says that the scale factor between triangles A and B is 12. Why is Sam not correct?

What number is one half times the size of 72?

Sam makes lemonade and uses 1 part lemon for every 3 parts water. If they use 33 parts water, how many parts of lemon will they need?

Sam makes lemonade and uses 1 part lemon for every 3 parts water. If they use 8 parts lemon, how many parts of water will they need?

A quiz team is made up of 3 adults and 4 children. If there are 63 people taking part. Which equation represents the number of teams taking part?

A quiz team is made up of 3 adults and 4 children. If there are 63 people taking part, how many of them are children?

This lesson will soon be taken down.

Identify and describe the relationship between regular polygons using scale factors

Lesson outcome