Finding the Fourth Proportional to 155,986.56, 215,271.28 and 87,978.72

Step by Step Solution

1. Step 1: Write the proportion equation
   155,986.56 : 215,271.28 = 87,978.72 : x
2. Step 2: Convert to fraction form
   155,986.56/215,271.28 = 87,978.72/x
3. Step 3: Cross multiply
   155,986.56x = 215,271.28 × 87,978.72
4. Step 4: Simplify right side
   155,986.56x = 18,939,291,667.16
5. Step 5: Solve for x
   x = 18,939,291,667.16/155,986.56
6. Step 6: Final answer
   x = 121,416.18