Well, to start off you divide 8.5 by 100, this gives you 0.085.
This, when multiplied by 1000 to make it a whole number equals

When simplified this will equal
Dividing by 10 is simple; just move the decimal place one digit to the left. So, 8.0 would then be 0.8. However, it is imperative you show your working out:
8/10=0.8
Let the number be x.
2x-3=55
2x=55-3
2x=52
x=52/2
x=26
When you have an irregular figure, you can divide it so that it becomes multiple normal figures. You already did this in the picture, now you just have to find the area of each shape and then add them all together.
From bottom to top:
A=1/2 (b1+b2)h
A= 1/2 (4+2.24)(2)
A= 6.24
(you have two of these on either side)
A=bh
A=6(4)
A=24
A=1/2 bh
A= 1/2 (4)(4)
A=8
(NOTE: there is an error in your drawing. The height of the triangle cant be determined because the 10 value spans over the entire figure when the wings of the rocket are 4 units long and then the body is 6 units long, making it equal 10 already. I'm assuming that the 10 is supposed to go from the bottom of the rectangle to the top of the triangle)
Total figure= 6.24 + 6.24 + 24 + 8
total figure = 44.48