Scale Factor Review Notes

A scale drawing represents an object with dimensions reduced or enlarged.

Two shapes are proportional if they have the same shape but different sizes, maintaining a constant ratio.

Scale factor is the ratio of new object length to the original object length.

Perimeter: Sum of the side lengths of a polygon.

Area: Measure of the inside region of a closed 2D figure (Triangle: (12∗base∗height)(\frac{1}{2} * base * height), Square: (side2)(side^2), Rectangle: (length∗width)(length * width), Circle: (π∗radius2)(\pi * radius^2)).

Scale factor > 1: Enlargement. Scale factor < 1: Reduction.

Finding Scale Factor: SideLengthofNewFigureCorrespondingSideLengthofOriginalFigure\frac{Side Length of New Figure}{Corresponding Side Length of Original Figure}

Calculating Dimensions: Multiply original dimensions by the scale factor.

Finding Perimeter: Multiply original dimensions by the scale factor, then calculate the perimeter.

Finding Area: Multiply original dimensions by the scale factor, then calculate the area (in square units).