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Finding the Fourth Proportional to 718.28, 991.17 and 407.78

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Solution

The fourth proportional to 718.28, 991.17 and 407.78 is: 562.70

Step by Step Solution

  1. Step 1: Write the proportion equation
    718.28 : 991.17 = 407.78 : x
  2. Step 2: Convert to fraction form
    718.28/991.17 = 407.78/x
  3. Step 3: Cross multiply
    718.28x = 991.17 × 407.78
  4. Step 4: Simplify right side
    718.28x = 404,179.30
  5. Step 5: Solve for x
    x = 404,179.30/718.28
  6. Step 6: Final answer
    x = 562.70

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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.