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Finding the Fourth Proportional to 717.79, 990.40 and 423.15

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Solution

The fourth proportional to 717.79, 990.40 and 423.15 is: 583.86

Step by Step Solution

  1. Step 1: Write the proportion equation
    717.79 : 990.40 = 423.15 : x
  2. Step 2: Convert to fraction form
    717.79/990.40 = 423.15/x
  3. Step 3: Cross multiply
    717.79x = 990.40 × 423.15
  4. Step 4: Simplify right side
    717.79x = 419,087.76
  5. Step 5: Solve for x
    x = 419,087.76/717.79
  6. Step 6: Final answer
    x = 583.86

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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.