Ratio - Calculating Scale Factors - Presentation

In a series of engaging and interactive slides, students delve into the concept of scale factors, a crucial component of understanding ratios in mathematics. The lesson aims to build upon their existing knowledge by teaching them how to calculate the scale factor used in scaling up or down various shapes. Initially, students are prompted to discuss what a scale factor is and to provide examples to solidify their comprehension. Subsequent activities involve comparing two shapes, typically labelled as Shape A and Shape B, where students must determine how many times larger Shape B is compared to Shape A. They are then tasked with identifying the scale factor by which Shape A has been enlarged to create Shape B, reinforcing their understanding through practical application.

Further activities include examining a set of rectangles that are similar to each other and calculating the scale factor of enlargement between them. Students are presented with tables showing the lengths and widths of different rectangles and are required to fill in missing information and complete sentences that articulate the scale factor. For example, they are given the dimensions of Rectangle A and must find the scale factors that relate Rectangle A to Rectangles B, C, and D. The lesson also incorporates reasoning tasks, where students are challenged to draw rectangles with given perimeters and lengths, and to determine whether certain statements about enlarging shapes are always, sometimes, or never true. The lesson concludes with independent work where students must read measurements, draw rectangles, and discuss concepts such as similarity and the implications of different scale factors.