Introduction to Scale Drawings
Introduction to Scale Drawings is a Grade 7 math skill in Illustrative Mathematics, Chapter 1: Scale Drawings. Students learn that a scale drawing accurately represents an object at a different size, with all lengths scaled by the same ratio, and the scale factor relating drawing measurements to actual measurements.
Key Concepts
Property A scale drawing is a proportional two dimensional (2D) drawing of an object. The scale is the ratio that relates the dimensions in the drawing to the actual dimensions of the object. Scale = Drawing Dimension : Actual Dimension.
Examples On a road map, the scale might be 1 inch : 10 miles. This means every 1 inch on the map represents an actual distance of 10 miles. The blueprint for a house uses a scale of 1/4 inch = 1 foot. Every quarter inch on the drawing corresponds to 1 foot of the actual house. A drawing of an insect in a science textbook might have a scale of 5 cm : 1 cm. This indicates the drawing is 5 times larger than the actual insect.
Explanation Scale drawings are used to accurately represent objects that are either too large or too small to be drawn at their actual size on paper. The scale ensures that all parts of the drawing are shrunk or enlarged by the same factor, maintaining the object's correct proportions.
Common Questions
What is a scale drawing?
A scale drawing is a drawing where all lengths are reduced or enlarged by the same ratio called the scale factor. The drawing looks like the original but is a different size.
What is a scale factor?
The scale factor is the ratio of a length in the drawing to the corresponding actual length. For example, a scale of 1:100 means 1 unit in the drawing equals 100 units in reality.
How do you find an actual length from a scale drawing?
Multiply the drawing length by the scale factor (actual to drawing ratio). Or divide the drawing length by the drawing-to-actual ratio.
What types of objects use scale drawings?
Maps, architectural blueprints, engineering diagrams, and model designs all use scale drawings to represent real objects at convenient sizes.
What chapter covers scale drawings in Illustrative Mathematics Grade 7?
Introduction to scale drawings is covered in Chapter 1: Scale Drawings in Illustrative Mathematics Grade 7.