Solve for w: ac = dw + b

Prove that 3: 8 is equivalent to 12: 32.a. use diagrams to support your answer.

Me because some of question i don’t understand

Gregory draws a scale drawing of his room. the scale that he uses is 1 cm : 4 ft. on his drawing, the room is 3 centimeters long. which equation can be used to find the actual length of gregory's room?