1. Because the area ratio is the square of the similarity ratio, (25/ 128) 2 is the area ratio between the dynamic version and the original version.

2. Solution: Set X books for the fifth grade. x+x( 1+50%)= 1000

2.5x= 1000

x=400

3. Solution: 3 1-28=3 (cm)

V=π r^2 h

=πX 15^2X3

=675π

If π is 3. 14, then

675x3. 14=2 1 19.5(cm^3)

There seems to be something wrong with this question.