the answer to your question is c
The answer is 21 which comes from 7 * 3.
Draw the four points in a complex plane. From the drawing you can see that the lenght is 4i - (-3i) = 4i + 3i = 7i, and the width is 1 - (-2) = 1 + 2 = 3.
So, the area is 7 * 3 = 21.
0.674 means that it 674/1000
which mean that if the model consists of 1000 squares, you have to shade 674 of the squares.
If the model consists of 500 squares, you have to shade 337 of the squares ( you get the number after dividing both 674 and 1000 with 2)
X=15degrees
The angle measurements are 30, 30, and 120 so it is an isosceles