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Scale Factor, Perimeter, Area and Volume of Similar Figures

Videos, worksheets, stories and songs to help Grade 8 students learn about Scale Factor.

In this lesson, we will learn the scale factors of similar figures, the ratio of lengths, perimeters, areas and volumes of similar figures.

Related Topics:
More Lessons for Grade 8 math
, More Geometry Lessons

Scale Factor

A scale factor is the factor by which all the components of an object are multiplied in order to create a proportional enlargement or reduction.

This video shows how to use scale to determine the dimensions of a proportional model.
Define scale factor. Use scale factor to sketch a proportional scale model.
Scale factor is a ratio comparing the scaled measurement to the actual measurement.
1. The scale factor of a model car is 1:24. If the actual car is 18 ft long and 8 ft wide, how long and wide will the model car be in inches?
2. You need to sketch a ladybug using a scale factor of 12. If a ladybug is 8 mm long and 4 mm wide, what will be the length and width of the sketch be in cm?
A brief course in scale factor for similar geometric figures
Scale Factor is defined as the ratio of any two corresponding lengths in two similar geometric figures.

Ratio of Perimeters and Areas

This video explains how to find the ratio of areas and ratios of perimeters for similar polygons
Ratio of perimeters = ratio of sides
Ratio of areas = (ratio of sides)2
Scale Factor/Perimeter Ratio/Area Ratio
Given that the polygon in each pair are similar. Find the scale factor, perimeter ratio and area ratio.

Areas and Perimeters of Similar Figures
This video discusses how to find the ratio of the perimeters and the ratio of the areas of similar figures from the scale factor. Also how to use these ratios to find missing perimeters and areas.
Scale factor effect on area and perimeter

Ratio of Surface Areas and Volumes

Scale Factor, Length, Area and Volume for similar shapes
Ratio of lengths = ratio of sides = scale factor
Ratio of surface areas = (ratio of sides)2 = (scale factor)2
Ratio of volume = (ratio of sides)3 = (scale factor)3
Similar Figures, Scale Factor, Area & Volume Ratios

Similar Figures, Scale Factor, Area & Volume Ratios
3D Figures - Scale Models and Factors
Learn about scaling 3D figures using scale factor

You can use the Mathway widget below to practice Algebra or other math topics. Try the given examples, or type in your own problem. Then click "Answer" to check your answer.

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