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Finding the Fourth Proportional to 781.50, 1,172.88 and 416.40

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Solution

The fourth proportional to 781.50, 1,172.88 and 416.40 is: 624.94

Step by Step Solution

  1. Step 1: Write the proportion equation
    781.50 : 1,172.88 = 416.40 : x
  2. Step 2: Convert to fraction form
    781.50/1,172.88 = 416.40/x
  3. Step 3: Cross multiply
    781.50x = 1,172.88 × 416.40
  4. Step 4: Simplify right side
    781.50x = 488,387.23
  5. Step 5: Solve for x
    x = 488,387.23/781.50
  6. Step 6: Final answer
    x = 624.94

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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.