Fiona, I did the same question earlier in the school year
The answer is (A) 15.
(6x -10) makes 80 and (6x+10) makes 100
together that equales 180 degrees. since it is a straight line the sum of the the two would have to equal 180. hope this helped :D
If it is being connected then it is a chord. If it directly goes thru the middle point in a circle, it is either a radius or diameter based on the length.
