The angle at the circumference in a semicircle is a right angle ... The angle between a tangent and a radius is 90°.. Angle OCA and OBA are both 90°. OB = OC because they are both radii of ...

the radius will be equal to 34cm. DRESS MAKER:'So two multiplied by pi multiplied by 34, is equal to213.628cm. DRESS MAKER:'However, I will be using a semicircle, so I need to divide the ...

An alternative is to define π to be twice the area of the same semicircle: The upshot of all of this is that π isn't as simple to define as you've been led to believe your whole life.