Answer:

Step-by-step explanation:
We see that diagonal AB is also the hypotenuse of a triangle where the other 2 side lengths are 4 and sqrt{45}. Using the Pythagorean theorem, we get that diagonal AB is 
The original is 5cm, the reduced is 2.5cm
2.5/5 = 0.5 = 1/2
Area is a square measurement, so the area of the reduced image would be the scale squared, which would be 1/2^2 which = 1/4
The answer is:
The area of the reduced design is 1/4 of the area of the original.