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Finding the Fourth Proportional to 717.78, 990.54 and 407.28

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Solution

The fourth proportional to 717.78, 990.54 and 407.28 is: 562.05

Step by Step Solution

  1. Step 1: Write the proportion equation
    717.78 : 990.54 = 407.28 : x
  2. Step 2: Convert to fraction form
    717.78/990.54 = 407.28/x
  3. Step 3: Cross multiply
    717.78x = 990.54 × 407.28
  4. Step 4: Simplify right side
    717.78x = 403,427.13
  5. Step 5: Solve for x
    x = 403,427.13/717.78
  6. Step 6: Final answer
    x = 562.05

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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.