Answer:

Step-by-step explanation:
The general equation for a circle is

Where a and b are the x and y values of the centre. So comparing to your equation you can see that a is 2/3 and b is 0
Try 18 and then multiply the sum of 2 and 18 to 7
Answer:
angle BEF = 100 degrees
Step-by-step explanation:
For a regular 9-sided polygon (nonagon),
each exterior angle = 360/9=40 degrees
each interior angle = 180-40 = 140 degrees.
Referring to diagram, in the trapezoid (trapezium) BCDE, the base angles are 180-140 = 40 degrees.
Therefore angle DEB = 40 degrees
that leaves BEF = 140-40 = 100 degrees
angle BCA would be 60, so 50 + 60 = 110, so angle CAB would be 70
D - their slopes are negative reciprocals of each other.