Lesson 22 — Activity 2: Scale and Proportions
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Lesson 22 — Activity 2:
Scale and Proportions
Lesson 22 — Activity 2:
Scale and Proportions
Scale is important in design work or customer service work. If a customer brings in a photo to be reproduced as a mural on a wall, you must calculate scale.
Image Source: Pixabay
In the last lesson, you learned about ratio. Remember, ratio says how much of one of thing there is compared to another thing. We write ratio like this: 1:4 or like a fraction 1/4, and we say the ratio is one to four.
Proportion is an equation with a ratio on each side. Proportion says that two ratios (or fractions) are equal. In the example below, if you multiply both the top and bottom of the fraction 1/3 by 2, you get the fraction 2/6. Therefore, these two ratios
(or fractions) are equal.
Are these ratios proportional?
3:4 and 6:8
Yes! The ratios are proportional because each of the ratios were multiplied by the same number:
3 x 2 = 6 and 4 x 2 = 8
so these numbers are in proportion!
Let's try another one!
1:4 and 3:16
No, these ratios are NOT proportional because each ratio was not multiplied by the same number:
1 x 3 = 3 and 4 x 4 = 16
1:4 and 3:16
No, these ratios are NOT proportional because each ratio was not multiplied by the same number:
1 x 3 = 3 and 4 x 4 = 16
1 x 3 = 3 and 4 x 4 = 16
Self-check!
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