Pie (3.14159...) times (*) 2 times (*) radius === or This equation may be for the area but hopefully it's for circumference. Anyway, the answer to your question is 25.13274123... (Pie times 2 times 4mm).
151200
Area of a circle = Pi * radius2
the area of the circle is increased by 400%
Area of a circle = pi*radius2
A circle with a diameter of 4 mm has an area of : 12.57 mm2
50.265 square mm
You neglected to say whether the 4mm is the radius of the circle, or the diameter,or the circumference. Each possibility gives you a different area.
Using 3.14 as Pi the area of circle is: 50.24
Pie (3.14159...) times (*) 2 times (*) radius === or This equation may be for the area but hopefully it's for circumference. Anyway, the answer to your question is 25.13274123... (Pie times 2 times 4mm).
151200
127.5
h = 5.9949 m
A 4mm diamond measures 4mm in at least one measurement.
4mm is 0.15748032 of an inch.
4mm its in the question
As wide as 4mm on a ruler