Answer:
a = 133 degrees
b = 78 degrees
Explanation:
the top and bottom lines are parallel.
the two sidelines are lines that intercept the top and bottom lines.
as they intercept parallel lines, they actually must have the same angles with them.
so, the 47 degrees inner angle at the bottom line, must be also somewhere at the interception point with the top line. and right, it must be now mirrored the outward angle at the top line. and that means a (the inward angle at the top line) is also the outward angle at the bottom line.
the sum of inward and outward angles at a point must always be 180 degrees.
so, the outward angle of 47 = the inward angle a =
= 180 - 47 = 133 degrees.
similar in the other side.
102 is the inward angle.
the outward angle of that is 180 - 102 = 78 degrees.
and that is also the inward angle b.
b = 78 degrees