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Finding the Fourth Proportional to 717.76, 990.56 and 423.20

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Solution

The fourth proportional to 717.76, 990.56 and 423.20 is: 584.05

Step by Step Solution

  1. Step 1: Write the proportion equation
    717.76 : 990.56 = 423.20 : x
  2. Step 2: Convert to fraction form
    717.76/990.56 = 423.20/x
  3. Step 3: Cross multiply
    717.76x = 990.56 × 423.20
  4. Step 4: Simplify right side
    717.76x = 419,204.99
  5. Step 5: Solve for x
    x = 419,204.99/717.76
  6. Step 6: Final answer
    x = 584.05

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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.