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Finding the Fourth Proportional to 128.55, 192.72 and 64.47

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Solution

The fourth proportional to 128.55, 192.72 and 64.47 is: 96.65

Step by Step Solution

  1. Step 1: Write the proportion equation
    128.55 : 192.72 = 64.47 : x
  2. Step 2: Convert to fraction form
    128.55/192.72 = 64.47/x
  3. Step 3: Cross multiply
    128.55x = 192.72 × 64.47
  4. Step 4: Simplify right side
    128.55x = 12,424.66
  5. Step 5: Solve for x
    x = 12,424.66/128.55
  6. Step 6: Final answer
    x = 96.65

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Why These Related Problems?

These problems maintain the same ratio (1.50) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.