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Finding the Fourth Proportional to 717.64, 990.54 and 520.78

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Solution

The fourth proportional to 717.64, 990.54 and 520.78 is: 718.82

Step by Step Solution

  1. Step 1: Write the proportion equation
    717.64 : 990.54 = 520.78 : x
  2. Step 2: Convert to fraction form
    717.64/990.54 = 520.78/x
  3. Step 3: Cross multiply
    717.64x = 990.54 × 520.78
  4. Step 4: Simplify right side
    717.64x = 515,853.42
  5. Step 5: Solve for x
    x = 515,853.42/717.64
  6. Step 6: Final answer
    x = 718.82

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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.