Finding the Fourth Proportional to 99.72, 137.61 and 56.06

Step by Step Solution

1. Step 1: Write the proportion equation
   99.72 : 137.61 = 56.06 : x
2. Step 2: Convert to fraction form
   99.72/137.61 = 56.06/x
3. Step 3: Cross multiply
   99.72x = 137.61 × 56.06
4. Step 4: Simplify right side
   99.72x = 7,714.42
5. Step 5: Solve for x
   x = 7,714.42/99.72
6. Step 6: Final answer
   x = 77.36