<u>ANSWER TO PART A</u>
The given triangle has vertices 
The mapping for rotation through
counterclockwise has the mapping

Therefore



We plot all this point and connect them with straight lines.
ANSWER TO PART B
For a reflection across the y-axis we negate the x coordinates.
The mapping is

Therefore



We plot all this point and connect them with straight lines.
See graph in attachment
Answer:
Area of the sector = 57.26295cm²
Step-by-step explanation:
Radius of the circle=9cm
π= 3.142
Angle at B= 81° ( opposite angle of a quadrilateral)
Area of the sector = πr² * 81/360
Area of the sector = 3.142 * 9*9 * 0.225
Area of the sector= 3.142*81*0.225
Area of the sector = 57.26295cm²