Proportions

Front

What is a proportion?

Back

A proportion is an equation that states that two ratios are equal.

Front

How do you determine if two ratios form a proportion?

Back

Two ratios form a proportion if the cross products are equal.

Front

What is the cross product of the ratios \( \frac{a}{b} \) and \( \frac{c}{d} \)?

Back

The cross product is \( a \times d \) and \( b \times c \). If \( a \times d = b \times c \), then the ratios form a proportion.

Front

If \( \frac{2x}{20} = \frac{2}{4} \), what is the value of x?

Back

x = 5.

Front

If there are 6 red cars sold for every 3 blue cars, what is the ratio of red cars to blue cars?

Back

The ratio is 6:3, which simplifies to 2:1.

Front

Is the ratio 2:1 equivalent to the ratio 6:3?

Back

Yes, they are equivalent ratios.

Front

What is the unit rate?

Back

The unit rate is a comparison of two different quantities when they are combined together, expressed as a quantity per one unit.

Front

If 2 apples cost $20, what is the cost of 1 apple?

Back

The cost of 1 apple is $10.

Front

If 2 apples cost $20, how much do 5 apples cost?

Back

5 apples cost $50.

Front

What is the formula for finding a missing value in a proportion?

Back

If \( \frac{a}{b} = \frac{c}{d} \), then \( a \times d = b \times c \).