Question

If two congruent angles form a linear pair, then __________.
A.
one angle is acute and the other angle is obtuse
B.
they are both right angles
C.
they are both acute angles
D.
they are both obtuse angles

Answer 1

You know what linear pair means?

Answer 2

Linear Pair is a pair of adjacent angles that form a straight line.

Answer 3

Yes, so their sum total is the measure of a straight line (angle). What's the measure of a straight angle?

Answer 4

180 degrees

Answer 5

So, say, choice C... they are both acute angles, in other words, both angles measure less than 90 degrees, can they EVER sum up to 180 degrees?

Answer 6

yes

Answer 7

No...
they can't
Say your angles are A and B
if
A < 90
B < 90
(in other words, both A and B are acute)

then
A + B < 180

Then, if both angles are acute, they cannot form a linear pair, as they cannot sum up to 180. Use similar reasoning for choice D.