<Tr> <Td> <Ul> <Li> </Li> <Li> </Li> <Li> </Li> </Ul> </Td> </Tr> <Ul> <Li> </Li> <Li> </Li> <Li> </Li> </Ul> <P> Compass - and - straightedge construction, also known as ruler - and - compass construction or classical construction, is the construction of lengths, angles, and other geometric figures using only an idealized ruler and compass . </P> <P> The idealized ruler, known as a straightedge, is assumed to be infinite in length, and has no markings on it with only one edge . The compass is assumed to collapse when lifted from the page, so may not be directly used to transfer distances . (This is an unimportant restriction since, using a multi-step procedure, a distance can be transferred even with collapsing compass; see compass equivalence theorem .) More formally, the only permissible constructions are those granted by Euclid's first three postulates . </P>

A geometry ruler can be constructed by using what tools