Finding the Fourth Proportional to 99.89, 137.86 and 56.24

Step by Step Solution

1. Step 1: Write the proportion equation
   99.89 : 137.86 = 56.24 : x
2. Step 2: Convert to fraction form
   99.89/137.86 = 56.24/x
3. Step 3: Cross multiply
   99.89x = 137.86 × 56.24
4. Step 4: Simplify right side
   99.89x = 7,752.42
5. Step 5: Solve for x
   x = 7,752.42/99.89
6. Step 6: Final answer
   x = 77.61