For the same reason they chose to measure volume in cubic units
they use protractors to measure circles
With a ruler
They are circles. We measure circles in degrees.
Protractors have to be half- circles because they measure angles less than 360 degrees.
Yes, two arcs with the same measure that are arcs of the same circle or congruent circles are congruent to each other. This means they have the same length and subtend the same angle at the center of their respective circles. Therefore, if the circles are congruent, the arcs will be identical in measure, regardless of the size of the circles.
To use a protractor for circles you find the middle of the circle and you then put the dot on the hole then you measure
Because they (IMO) have the simplest area to find, to just square side. Triangles are half of a square Rectangles are uneven. Circles are rounded, and hard to find the area of. Plus, a square has 2 equal dimensions, so think 2D.
Congruent circles, maybe...
Congruent Arcs
Archimedes of Syracuse
A protractor measures the degree of angles and circles.
same circle or congruent circles