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Finding the Fourth Proportional to 689.31, 951.18 and 390.57

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Solution

The fourth proportional to 689.31, 951.18 and 390.57 is: 538.94

Step by Step Solution

  1. Step 1: Write the proportion equation
    689.31 : 951.18 = 390.57 : x
  2. Step 2: Convert to fraction form
    689.31/951.18 = 390.57/x
  3. Step 3: Cross multiply
    689.31x = 951.18 × 390.57
  4. Step 4: Simplify right side
    689.31x = 371,495.66
  5. Step 5: Solve for x
    x = 371,495.66/689.31
  6. Step 6: Final answer
    x = 538.94

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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.