It is B=24
Hope this helps:)
The second in the top row is this:
42.4-1.5(TIMES)3.1
42.4-46.5
-4.1
Mrs.Kennedy can divide 315 by 10 and then when she gets her answer she can round up to get her answer.
AC is a tangent so by definition, it touches the circle at exactly one point (point C) and forms a right angle at the tangency point. So angle ACO is 90 degrees
The remaining angle OAC must be 45 degrees because we need to have all three angles add to 180
45+45+90 = 90+90 = 180
Alternatively you can solve algebraically like so
(angle OAC) + (angle OCA) + (angle COA) = 180
(angle OAC) + (90 degrees) + (45 degrees) = 180
(angle OAC) + 90+45 = 180
(angle OAC) + 135 = 180
(angle OAC) + 135 - 135 = 180 - 135
angle OAC = 45 degrees
Side Note: Triangle OCA is an isosceles right triangle. It is of the template 45-45-90.
Reflecting across the x axis maintains the same x coordinate, but changes the sign of the y coordinate.
So, the transformation is
