Finding Ratios of Corresponding Measurements
Finding ratios of corresponding measurements in similar figures is a Grade 7 geometry skill in Big Ideas Math Advanced 2, Chapter 2: Transformations. For similar figures, the ratio of corresponding sides remains constant and equals the scale factor. For example, if triangle ABC has sides 6, 8, 10 and similar triangle DEF has sides 9, 12, 15, the ratio is 6:9 equals 8:12 equals 10:15 equals 2:3.
Key Concepts
For similar figures, the ratio of corresponding measurements is found by dividing one measurement by its corresponding measurement in the other figure: $\frac{\text{measurement} 1}{\text{measurement} 2}$.
Common Questions
How do you find the ratio of corresponding measurements in similar figures?
Divide one measurement by its corresponding measurement in the other figure. The ratio should be the same for all corresponding sides, expressed as a fraction, decimal, or using colon notation.
What does a constant ratio between corresponding sides mean?
A constant ratio means the two figures are similar — they have the same shape but different sizes. The constant ratio is the scale factor between the figures.
Can the ratio be expressed in different ways?
Yes, the same ratio can be written as a fraction (2/3), decimal (0.667), or colon notation (2:3). All represent the same scale factor.
What textbook covers finding ratios of corresponding measurements in Grade 7?
Big Ideas Math Advanced 2, Chapter 2: Transformations covers finding and using ratios of corresponding measurements in similar figures.