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Finding the Fourth Proportional to 865.72, 1,299 and 455.20

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Solution

The fourth proportional to 865.72, 1,299 and 455.20 is: 683.02

Step by Step Solution

  1. Step 1: Write the proportion equation
    865.72 : 1,299 = 455.20 : x
  2. Step 2: Convert to fraction form
    865.72/1,299 = 455.20/x
  3. Step 3: Cross multiply
    865.72x = 1,299 × 455.20
  4. Step 4: Simplify right side
    865.72x = 591,304.80
  5. Step 5: Solve for x
    x = 591,304.80/865.72
  6. Step 6: Final answer
    x = 683.02

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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.