When dealing with little odds you must know one part and the whole part. For number 1 a fraction , 7 is a part of a 11 which is the whole. For 2 a percent, 6% part and 100% whole, here you had to know that for 6% to exist there had to be a 100% . For 3 a ratio, the first number is part (2) and the second is whole (7). Look at pic for all work.
Answer:
The value of A is 20
Step-by-step explanation:
To find the answer, note that all triangles have a interior degree measurement of 180. Set the sum of the angles equal to 180.
71x - 1 + 20x + 90 = 180
91x + 89 = 180
91x = 91
x = 1
Now we can use this in the A angle to find the value.
A = 20x
A = 20(1)
A = 20
I agree with your answer "supplementary". The two angles combine to form 180 degrees, aka a straight angle
Your teacher seemed to have made a typo.