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Finding the Fourth Proportional to 716.88, 989.20 and 406.40

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Solution

The fourth proportional to 716.88, 989.20 and 406.40 is: 560.78

Step by Step Solution

  1. Step 1: Write the proportion equation
    716.88 : 989.20 = 406.40 : x
  2. Step 2: Convert to fraction form
    716.88/989.20 = 406.40/x
  3. Step 3: Cross multiply
    716.88x = 989.20 × 406.40
  4. Step 4: Simplify right side
    716.88x = 402,010.88
  5. Step 5: Solve for x
    x = 402,010.88/716.88
  6. Step 6: Final answer
    x = 560.78

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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.