Hello there.
You have been asked to build a scale model of your school out of toothpicks. imagine your school is 30ft tall. your scale is 1ft:26cm
Answer: Since you have one part of the input data in the ratio , you can insert it.
At the moment it would look like this 30ft : ? . To get from 1 to 30 you have to multiply by 30 therefore you should do that to the other side too.
26cm x 30 = 780.
Therefore the scale is now 30ft : 780 cm.
Hope This Helps You!
Good Luck Studying :)