The radius of a circle is half the diameter.
with a big tape measure
measure it÷ it by 2.
Measure the diametre of the circle and divide by two to give the radius.
you have a triangle formed by the radius on 2 and the chord on the other. the angle in that triangle that is opposite the chord, find its measure in radians take that measure (in radians) and multiply it by the radius to get the arc length
To get the area of a piston, you need to measure the diameter or radius of the piston head and use the formula for the area of a circle (A = πr^2) where r is the radius of the piston head. Once you have the radius, plug it into the formula to calculate the area of the piston head.
The radius of a circle is half the diameter.
at the distal end of the radius
measure from the middle out to one side
head of radius
with a big tape measure
7.4
measure it
measure it÷ it by 2.
If you have a physical cylinder to measure, measure the "width" of the circle that is the cross section of the cylinder. That is the diameter, Half the diameter is the radius.
You can measure the diameter, then divide that by 2.
The teacher explained how to measure the area of a circle using radius.