Finding the Fourth Proportional to 128.49, 176.91 and 100.50

Step by Step Solution

1. Step 1: Write the proportion equation
   128.49 : 176.91 = 100.50 : x
2. Step 2: Convert to fraction form
   128.49/176.91 = 100.50/x
3. Step 3: Cross multiply
   128.49x = 176.91 × 100.50
4. Step 4: Simplify right side
   128.49x = 17,779.46
5. Step 5: Solve for x
   x = 17,779.46/128.49
6. Step 6: Final answer
   x = 138.37