If we know the distance something has moved and the time it has taken, we can calculate its speed. We can calculate each using the triangle opposite. Speed, distance and time are called variables .

With a wide-angle zoom setting and narrow aperture, the hyperfocal distance will therefore be very much closer. In this case, it would be 77cm as opposed to 28.2m (see table).

Pszczolkowski adds, “I’ll often calculate mpg and the distance-to-empty, and it’s usually very close to the car’s reading.” In most cars, the low-fuel light generally comes on when you ...