Radii are always positive. No, it is not possible to draw a circle with negative radius.
1 centimeter
Yes
The diameter is a straight line from one side of the circle to the other which passes through the centre of the circle. The radius is a straight line from the centre to the boundary of the circle. To label them, you could either write the words alongside the lines or, if the circle is too small, draw arrows from the two lines to outside the circle and write the words at the end of the arrow.
Make a sketch of the situation. From a corner of the equilateral triangle draw a radius of the large circle, and from an adjacent side draw a radius of the smaller circle. You should have formed a small right-angled triangle with a known side of 10cm. and known angles of 30o, 60o and 90o. (The interior angles of an equilateral triangle are each 60o.) The hypotenuse is the unknown radius of the larger circle. But since cos 60 = 0.5, it is evident that the hypotenuse is 20cm. long.
It is possible. Just keep the drawing instrument 15.915 cm from a set point (the circle's center).
No, the circumference divided by the radius will always be pi for a circle.
A line of any length may act as the radius of a circle. The radius is the distance from the centre to the perimeter of a circle.
With a compass
In QBasic, you can draw a circle using the CIRCLE statement. The syntax is CIRCLE (x, y), radius, where (x, y) is the center of the circle, and radius is the radius of the circle. For example, CIRCLE (100, 100), 50 would draw a circle with a center at coordinates (100, 100) and a radius of 50 pixels. You can also specify a color by adding a third parameter, like CIRCLE (100, 100), 50, 15 for a circle in color 15.
Draw two diameters perpendicular to each other. Draw a smaller circle with the same centre such that the radius of the inner circle is 'r' and the radius of the outer circle is 'r√2.' [Or, the radius of the outer circle is R and the radius of the inner circle is R/√2.]
If you draw a line from the center of a circle to the edge of a circle, you have drawn the radius of the circle. If you draw a line from the edge of a circle through the center of the circle and on to the edge on the opposite side, you have drawn the diameter of a circle. The radius of a circle is one half the diameter of a circle.
1 centimeter
# Find the center of the circle # Draw the line of the radius from the center to the circumference # Finish
When you draw a circle in math, and you draw a triangle inside of it, 2 of the lines should be the radius of the circle, and the third (bottom) line that is not the radius is the chord.
The radius is the distance from the center of the circle to its edge. No matter how you draw this radius, it is one value of one length only, for any given circle.
The area of a circle is: pi times radius squared
To draw an arc in QBasic, you can use the Circle statement, specifying the center coordinates, radius, and the starting and ending angles. The syntax is Circle (x, y), radius, start_angle, end_angle. For example, Circle (100, 100), 50, 0, 90 would draw a quarter-circle arc from 0 to 90 degrees centered at (100, 100) with a radius of 50.