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Finding the Fourth Proportional to 639.22, 882.16 and 390.53

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Solution

The fourth proportional to 639.22, 882.16 and 390.53 is: 538.95

Step by Step Solution

  1. Step 1: Write the proportion equation
    639.22 : 882.16 = 390.53 : x
  2. Step 2: Convert to fraction form
    639.22/882.16 = 390.53/x
  3. Step 3: Cross multiply
    639.22x = 882.16 × 390.53
  4. Step 4: Simplify right side
    639.22x = 344,509.94
  5. Step 5: Solve for x
    x = 344,509.94/639.22
  6. Step 6: Final answer
    x = 538.95

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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.