1a:
580 - (580 × .1) - 20
580 - (58) - 20
522 - 20
502
1b:
990 - (990 × .25) - 20
990 - (247.5) - 20
742.5 - 20
722.5
I'm not sure how to solve #2.
The scale is a representation of what the drawing is to real life. The drawing will tend to be represented by a fixed figure such as 1 cm. In this case for every cm of drawing it is a representation of 8 millimetres in real life, therefore the drawing is bigger than the object.
Answer:
Step-by-step explanation:
From the graph attached,
Coordinates of the vertices are,
Q(1, 3), R(3, -3), S(0, -2) and T(-2, 1)
Following the rule of translation by 3 units to the right and 2 units down 
(x, y) → (x+3, y-2)
Q(1, 3) → Q''(4, 1)
R(3, -3) → R"(6, -5)
S(0, -2) → S"(3, -4)
T(-2, 1) → T"(1, -1)
Following rule
(rotation of a point by 180° about the origin) will give the image points,
(x, y) → (-x, -y)
Q"(4, 1) → Q'(-4, -1)
R"(6, -5) → R'(-6, 5)
S"(3, -4) → S'(-3, 4)
T"(1, -1) → T'(-1, 1)
I think this is
4+3 = 7.
.. :))