The ratio 9:7 gives you following statement:
- Carl will win in 9 cases from 9+7=16;
- Carl will lose in 7 cases from 16.
Then the probability that Carl will lose is

Answer: 
Since the second angle + first angle is 90 degrees, the third angle must be 90 degrees to complete the 180 degrees in a circle.
Hope this helps!
<span>slope
m = (1 - 1)/(0 + 2) = 0
(x1, y1) as (-2, 1)
</span><span>point-slope form</span><span>
y - y1 = m(x - x1)
y - 1 = 0(x + 2)
y - 1 = 0
y = 1</span>