Finding the Fourth Proportional to 152.56, 210.56 and 100.15

Step by Step Solution

1. Step 1: Write the proportion equation
   152.56 : 210.56 = 100.15 : x
2. Step 2: Convert to fraction form
   152.56/210.56 = 100.15/x
3. Step 3: Cross multiply
   152.56x = 210.56 × 100.15
4. Step 4: Simplify right side
   152.56x = 21,087.35
5. Step 5: Solve for x
   x = 21,087.35/152.56
6. Step 6: Final answer
   x = 138.22