+9466 a.
A minor arc is an arc that measures less than 180º
The minor arcs are: arc AB
arc AD
arc BC
arc BD
arc CD
b.
A semicircle is an arc that measures exactly 180º
The semicircles are: arc ABC and arc ADC
c.
A major arc is an arc that measures more than 180º
The major arcs are: arc ADB
arc ABD
arc BAC
arc BAD
arc CAD
To find all the major arcs, I looked at the minor arcs and stated the alternate way to connect those two points. Notice that the first and last letters are the same.
