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Finding the Fourth Proportional to 718.73, 991.85 and 399.69

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Solution

The fourth proportional to 718.73, 991.85 and 399.69 is: 551.57

Step by Step Solution

  1. Step 1: Write the proportion equation
    718.73 : 991.85 = 399.69 : x
  2. Step 2: Convert to fraction form
    718.73/991.85 = 399.69/x
  3. Step 3: Cross multiply
    718.73x = 991.85 × 399.69
  4. Step 4: Simplify right side
    718.73x = 396,432.53
  5. Step 5: Solve for x
    x = 396,432.53/718.73
  6. Step 6: Final answer
    x = 551.57

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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.