## Elementary Geometry for College Students (6th Edition)

First we can use a straight edge to draw a straight line. We can use a compass to draw a circle of radius $R$ such that the center of this circle is on the straight line. Using the compass, we can draw four more circles of radius $R$ such that the center of each successive circle is a point where the previous circle intersects the straight line. We can use the compass to draw a large circle of radius $2R$. Note that the two blue circles are externally tangent.