Directions: Solve Each Proportion.13. $\frac{9}{16}=\frac{x}{12}$15. $\frac{7}{11}=\frac{18}{x+1}$17. $\frac{17}{15}=\frac{10}{2x-2}$19. 6 19 = X − 12 2 X − 2 \frac{6}{19}=\frac{x-12}{2x-2} 19 6 ​ = 2 X − 2 X − 12 ​

What are Proportions?

A proportion is a statement that two ratios are equal. It is often written in the form of a fraction, where the numerator and denominator of the first fraction are equal to the numerator and denominator of the second fraction. Proportions are used to solve problems involving ratios and percentages.

Why are Proportions Important?

Proportions are used in a wide range of applications, including finance, science, and engineering. They are used to calculate interest rates, solve problems involving similar triangles, and determine the volume of a liquid.

How to Solve Proportions

To solve a proportion, we need to find the value of the variable that makes the two ratios equal. There are several methods to solve proportions, including:

• Cross-multiplication: This involves multiplying the numerator of the first fraction by the denominator of the second fraction, and then setting the result equal to the product of the denominator of the first fraction and the numerator of the second fraction.
• Inverse proportion: This involves finding the inverse of one of the ratios and then multiplying it by the other ratio.
• Proportion tables: This involves creating a table of values for the two ratios and then finding the value of the variable that makes the two ratios equal.

Solving the Given Proportions

13. $\frac{9}{16}=\frac{x}{12}$

To solve this proportion, we can use cross-multiplication. We multiply the numerator of the first fraction (9) by the denominator of the second fraction (12), and then set the result equal to the product of the denominator of the first fraction (16) and the numerator of the second fraction (x).

$$9 \times 12 = 16 \times x$$

Simplifying the equation, we get:

$$108 = 16x$$

Dividing both sides by 16, we get:

$$x = \frac{108}{16}$$

Simplifying the fraction, we get:

$$x = \frac{27}{4}$$

Therefore, the value of x is $\frac{27}{4}$.

15. $\frac{7}{11}=\frac{18}{x+1}$

To solve this proportion, we can use cross-multiplication. We multiply the numerator of the first fraction (7) by the denominator of the second fraction (x+1), and then set the result equal to the product of the denominator of the first fraction (11) and the numerator of the second fraction (18).

$$7 \times (x+1) = 11 \times 18$$

Simplifying the equation, we get:

$$7x + 7 = 198$$

Subtracting 7 from both sides, we get:

$$7x = 191$$

Dividing both sides by 7, we get:

$$x = \frac{191}{7}$$

Therefore, the value of x is $\frac{191}{7}$.

17. $\frac{17}{15}=\frac{10}{2x-2}$

To solve this proportion, we can use cross-multiplication. We multiply the numerator of the first fraction (17) by the denominator of the second fraction (2x-2), and then set the result equal to the product of the denominator of the first fraction (15) and the numerator of the second fraction (10).

$$17 \times (2x-2) = 15 \times 10$$

Simplifying the equation, we get:

$$34x - 34 = 150$$

Adding 34 to both sides, we get:

$$34x = 184$$

Dividing both sides by 34, we get:

$$x = \frac{184}{34}$$

Simplifying the fraction, we get:

$$x = \frac{92}{17}$$

Therefore, the value of x is $\frac{92}{17}$.

19. $\frac{6}{19}=\frac{x-12}{2x-2}$

To solve this proportion, we can use cross-multiplication. We multiply the numerator of the first fraction (6) by the denominator of the second fraction (2x-2), and then set the result equal to the product of the denominator of the first fraction (19) and the numerator of the second fraction (x-12).

$$6 \times (2x-2) = 19 \times (x-12)$$

Simplifying the equation, we get:

$$12x - 12 = 19x - 228$$

Adding 12 to both sides, we get:

$$12x = 19x - 216$$

Subtracting 19x from both sides, we get:

$$-7x = -216$$

Dividing both sides by -7, we get:

$$x = \frac{216}{7}$$

Therefore, the value of x is $\frac{216}{7}$.

Conclusion

Q: What is a proportion?

A: A proportion is a statement that two ratios are equal. It is often written in the form of a fraction, where the numerator and denominator of the first fraction are equal to the numerator and denominator of the second fraction.

Q: Why are proportions important?

A: Proportions are used in a wide range of applications, including finance, science, and engineering. They are used to calculate interest rates, solve problems involving similar triangles, and determine the volume of a liquid.

Q: How do I solve a proportion?

A: There are several methods to solve proportions, including:

• Cross-multiplication: This involves multiplying the numerator of the first fraction by the denominator of the second fraction, and then setting the result equal to the product of the denominator of the first fraction and the numerator of the second fraction.
• Inverse proportion: This involves finding the inverse of one of the ratios and then multiplying it by the other ratio.
• Proportion tables: This involves creating a table of values for the two ratios and then finding the value of the variable that makes the two ratios equal.

Q: What is cross-multiplication?

A: Cross-multiplication is a method of solving proportions that involves multiplying the numerator of the first fraction by the denominator of the second fraction, and then setting the result equal to the product of the denominator of the first fraction and the numerator of the second fraction.

Q: How do I use cross-multiplication to solve a proportion?

A: To use cross-multiplication to solve a proportion, follow these steps:

1. Multiply the numerator of the first fraction by the denominator of the second fraction.
2. Multiply the denominator of the first fraction by the numerator of the second fraction.
3. Set the two products equal to each other.
4. Solve for the variable.

Q: What is an inverse proportion?

A: An inverse proportion is a proportion where the product of the two ratios is equal to 1.

Q: How do I use inverse proportion to solve a proportion?

A: To use inverse proportion to solve a proportion, follow these steps:

1. Find the inverse of one of the ratios.
2. Multiply the inverse by the other ratio.
3. Set the result equal to 1.
4. Solve for the variable.

Q: What is a proportion table?

A: A proportion table is a table of values for the two ratios in a proportion.

Q: How do I use a proportion table to solve a proportion?

A: To use a proportion table to solve a proportion, follow these steps:

1. Create a table of values for the two ratios.
2. Find the value of the variable that makes the two ratios equal.
3. Use the table to find the value of the variable.

Q: What are some common mistakes to avoid when solving proportions?

A: Some common mistakes to avoid when solving proportions include:

• Not following the order of operations: Make sure to follow the order of operations when solving a proportion.
• Not simplifying the equation: Make sure to simplify the equation before solving for the variable.
• Not checking the solution: Make sure to check the solution to make sure it is correct.

Conclusion

Solving proportions is an important skill in mathematics, and it has many real-world applications. By following the steps outlined in this article, you should be able to solve proportions with ease. Remember to avoid common mistakes and to check your solution to make sure it is correct.