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Finding the Fourth Proportional to 717.78, 990.45 and 407.22

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Solution

The fourth proportional to 717.78, 990.45 and 407.22 is: 561.91

Step by Step Solution

  1. Step 1: Write the proportion equation
    717.78 : 990.45 = 407.22 : x
  2. Step 2: Convert to fraction form
    717.78/990.45 = 407.22/x
  3. Step 3: Cross multiply
    717.78x = 990.45 × 407.22
  4. Step 4: Simplify right side
    717.78x = 403,331.05
  5. Step 5: Solve for x
    x = 403,331.05/717.78
  6. Step 6: Final answer
    x = 561.91

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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.