Question 750074
Given: Width of garage (in diagram)= 5 cm
       Width of garage (actual)    = 4 cm

Then you have a fraction to multiply the other
sizes in the diagram namely: 4/5

Diagram width = 5cm x 4/5 = 4cm
Diagram length = 10cm x 4/5 = 8cms
Diagram height = 6cm  x 4/5 = 4.8cms

:-)