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Finding the Fourth Proportional to 392.78, 542.19 and 282.32

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Solution

The fourth proportional to 392.78, 542.19 and 282.32 is: 389.71

Step by Step Solution

  1. Step 1: Write the proportion equation
    392.78 : 542.19 = 282.32 : x
  2. Step 2: Convert to fraction form
    392.78/542.19 = 282.32/x
  3. Step 3: Cross multiply
    392.78x = 542.19 × 282.32
  4. Step 4: Simplify right side
    392.78x = 153,071.46
  5. Step 5: Solve for x
    x = 153,071.46/392.78
  6. Step 6: Final answer
    x = 389.71

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Why These Related Problems?

These problems maintain the same ratio (1.38) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.