How to find the scale factor of two triangles

Here's how to do it.  

Step-by-step explanation:

The two triangles must be similar, that is, corresponding angles must be equal, as in the diagram below.

1. Find a corresponding pair of sides

Assume that ∆ABC is the original and ∆DEF is its scaled image.

Then, AB and DE are corresponding sides, with lengths of 8 and 12 units , respectively.

2. Set up a ratio

Ratio = side length in image/side length in original = 12/8

3. Simplify the ratio

The simplified ratio is the scale factor (SF).

SF = 12/8 = 3/2 = 1.5

The scale factor is 1.5.

he spend 5.1 minutes chatting with his friends

step-by-step explanation:

2/5+1/2=9/10

6/1-9/10=5 1/10