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Finding the Fourth Proportional to 781.59, 1,178.24 and 728.74

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Solution

The fourth proportional to 781.59, 1,178.24 and 728.74 is: 1,098.57

Step by Step Solution

  1. Step 1: Write the proportion equation
    781.59 : 1,178.24 = 728.74 : x
  2. Step 2: Convert to fraction form
    781.59/1,178.24 = 728.74/x
  3. Step 3: Cross multiply
    781.59x = 1,178.24 × 728.74
  4. Step 4: Simplify right side
    781.59x = 858,630.62
  5. Step 5: Solve for x
    x = 858,630.62/781.59
  6. Step 6: Final answer
    x = 1,098.57

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Why These Related Problems?

These problems maintain the same ratio (1.51) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.