You can name Plane P, many different ways,
Assuming you are asking this out of a textbook staring at a figure of a Parallelogram, their are probably points inside that shape and the way you would name it would be naming using any three points in the plane that are NOT on the same line in any order. <span />
Answer:
38.7
Step-by-step explanation:

A, B and C are the sides of the triangle and sinA, sinB and sinC are the opposing angles


Answer:

Step-by-step explanation:

Answer:
12 feet
Step-by-step explanation:
By Pythagoras theorem, a²+b²=c², where c represents the diagonal and a and b represents the other sides of a right angled triangle
As a flag is a rectangle, the two triangles cut would be right angled triangles
Therefore, a²+9²=15²
a²+81=225
a²=144
a=√144
a=12 feet