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Finding the Fourth Proportional to 680.40, 938.88 and 400.72

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Solution

The fourth proportional to 680.40, 938.88 and 400.72 is: 552.95

Step by Step Solution

  1. Step 1: Write the proportion equation
    680.40 : 938.88 = 400.72 : x
  2. Step 2: Convert to fraction form
    680.40/938.88 = 400.72/x
  3. Step 3: Cross multiply
    680.40x = 938.88 × 400.72
  4. Step 4: Simplify right side
    680.40x = 376,227.99
  5. Step 5: Solve for x
    x = 376,227.99/680.40
  6. Step 6: Final answer
    x = 552.95

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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.