Finding the Fourth Proportional to 72.16, 99.70 and 53.71

Step by Step Solution

1. Step 1: Write the proportion equation
   72.16 : 99.70 = 53.71 : x
2. Step 2: Convert to fraction form
   72.16/99.70 = 53.71/x
3. Step 3: Cross multiply
   72.16x = 99.70 × 53.71
4. Step 4: Simplify right side
   72.16x = 5,354.89
5. Step 5: Solve for x
   x = 5,354.89/72.16
6. Step 6: Final answer
   x = 74.21