If one foot is approximately 30 centimeters and one yard is about 90 centimeters, approximately how many feet are there in a yard?
This question is giving us proportions of feet to centimeters and one yard to centimeters. We can write one foot is approximately 30 centimeters, like this, one foot over 30 centimeters. One yard is approximately 90 centimeters, and we wanna replace this one yard with feet.
To get from 30 centimeters to 90 centimeters, we would multiply by three, and if we multiply our denominator by three, we’ll need to multiply our numerator by three. One times three is three. Using this proportion, we can see that there are three feet per yard.