Conversion: Miles to Kilometers

We frequently encounter distances in miles (English System), but in the Philippines, we use the metric system, and need to convert miles to kilometers,

We will use the conversion 1 mile = 1.6 km. And we have several ways to make the computation easier.  Let us consider two ways.

The easiest way to multiply buy 1.6 is by treating 1.6 as 1 + 0.5 + 0.1. Note that 0.5 is half of 1 and 0.1 is one tenth of 1.

  • 30 miles = 30 + ½(30) + 1/10 (30) =  30 + 15 + 3 = 48 km
  • 72 miles = 72 + 36 + 7.2 = 115.2 km
  • 114 miles = 114 + 57 + 11.4 = 182.4 km
  • 205 miles = 205 + 102.5 + 20.5 = 328 km

If we note that 1.6 = 16 / 10, we discover another way to multiply by1.6.  Simply  double the mile measure 4 times (multiply by 16) and move the decimal point of the final product one place to the left ( divide by 10).

  • 30 miles = 30 x 2 → 60 x 2 → 120 x 2 → 240 x 2 → 480 → 48 km
  • 72 miles = 72 x 2 → 144 x 2→ 288 x 2 → 576 x 2 → 1152 →  115.2 km
  • 114 miles = 114 x 2 → 228 x 2→ 456 x 2 → 912 x 2 → 1824 →  182.4 km
  • 205 miles = 205 x 2 → 410 x 2→ 820 x 2 → 1640 x 2 → 3280 → 328 km
1 mile is 1760 yards or 5280 feet which is equivalent to 1609.344 meters. For practical purposes we can use the conversion 1 mile = 1.6 kilometers. This is almost 99.5% accurate

C.)  A third way is to double the Mile measure and save it as the minuend; double it again and move the decimal point one place to the left to get the subtrahend; then perform the subtraction.

30 miles = 30 x 2 = 60;  60 x 2= 120 → 12.0; 60 – 12  → 48 km

72 miles = 72 x 2 = 144; 144 x 2=288  → 28.8; 144 – 28.8 =  115.2 km

114 miles = 114 x 2 = 228; 228 x 2=456  → 45.6; 228 – 45.6 = 182.4 km

205 miles = 205 x 2 = 410; 410 x 2 = 820 → 82.0; 410 – 82  = 328 km