Robin and Dovey have four pet pigeons that they train to race. They release the birds at Robin’s house and then drive to Dovey’s to collect
them. To drive from Robin’s to Dovey’s, because of one-way streets,
they go 3.1 km north, turn right and go 1.7 km east, turn left and go
2.3 km north, turn right and go 0.9 km east, turn left and go 1.2 km
north, turn left and go 4.1 km west, and finally turn left and go 0.4 km
south. How far do the pigeons have to fly to go directly from Robin’s
house to Dovey’s house?