Answer:
1A: The area of a flat, or plane figure is the number of unit squares that can be contained within it. The unit square is usually some standard unit, like a square meter, a square foot, or a square inch.
1B: A radius of a circle or sphere is any of the line segments from its center to its perimeter, and in more modern usage, it is also their length
1C: A diameter of a circle is any straight line segment that passes through the center of the circle and whose endpoints lie on the circle. It can also be defined as the longest chord of the circle.
2A: A=wl
2B: A=πr to the power of 2
Explanation: