An acute angle is infact 90 degrees, therefore your answer is correct.
Step-by-step explanation:
Consider Similarity and enlargement
To get the enlargement factor,
Take the ratio result of any two similar sides. i.e
PQ/AB = 3.6/2 = 1.8
The enlargement factor is 1.8
To get ST, consider ED then multiply it by the enlargement factor. i.e
= 5 x 1.8
= 9
12 are tankesr
40 cars total
12/40
12/40=6/20=3/10
3/10=tankders
10/10-3/10=7/10
7/10=70/100=70%
70% wern't tankser