Step-by-step explanation:

Answer:Side x side x side
Step-by-step explanation:
Since it is usually equally sided, it would be SxSxS
Answer:
,
, and 
Or
angle PQR, angle SQR and angle PQS
Step-by-step explanation:
The three different angles in the diagram are angle PQR, angle SQR and angle PQS.
Another way of writing this is using an angle sign before the alphabets follows. Thus:
,
, and