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Finding the Fourth Proportional to 720.78, 994.70 and 406.05

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Solution

The fourth proportional to 720.78, 994.70 and 406.05 is: 560.36

Step by Step Solution

  1. Step 1: Write the proportion equation
    720.78 : 994.70 = 406.05 : x
  2. Step 2: Convert to fraction form
    720.78/994.70 = 406.05/x
  3. Step 3: Cross multiply
    720.78x = 994.70 × 406.05
  4. Step 4: Simplify right side
    720.78x = 403,896.88
  5. Step 5: Solve for x
    x = 403,896.88/720.78
  6. Step 6: Final answer
    x = 560.36

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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.