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Finding the Fourth Proportional to 718.71, 1,078.20 and 285.90

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Solution

The fourth proportional to 718.71, 1,078.20 and 285.90 is: 428.90

Step by Step Solution

  1. Step 1: Write the proportion equation
    718.71 : 1,078.20 = 285.90 : x
  2. Step 2: Convert to fraction form
    718.71/1,078.20 = 285.90/x
  3. Step 3: Cross multiply
    718.71x = 1,078.20 × 285.90
  4. Step 4: Simplify right side
    718.71x = 308,257.38
  5. Step 5: Solve for x
    x = 308,257.38/718.71
  6. Step 6: Final answer
    x = 428.90

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Why These Related Problems?

These problems maintain the same ratio (1.50) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.