N / 2
400 / 2 = 200
200 / 2 = 100
100 / 2 = 50
50 / 2 = 25
25 / 2 = 12.5
2.45 cm= 1 in. so 100 cm must equal 39.37 in. because you already know 2.45 cm equals 1 inch and 1 metre equals 100 cm and 1 metre is equal to 39.37.
The first one since the given measurements/guide is Side, Angle, Side
