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Finding the Fourth Proportional to 128.31, 192.40 and 56.17

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Solution

The fourth proportional to 128.31, 192.40 and 56.17 is: 84.23

Step by Step Solution

  1. Step 1: Write the proportion equation
    128.31 : 192.40 = 56.17 : x
  2. Step 2: Convert to fraction form
    128.31/192.40 = 56.17/x
  3. Step 3: Cross multiply
    128.31x = 192.40 × 56.17
  4. Step 4: Simplify right side
    128.31x = 10,807.11
  5. Step 5: Solve for x
    x = 10,807.11/128.31
  6. Step 6: Final answer
    x = 84.23

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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.