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Finding the Fourth Proportional to 865.20, 1,297.62 and 378.12

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Solution

The fourth proportional to 865.20, 1,297.62 and 378.12 is: 567.10

Step by Step Solution

  1. Step 1: Write the proportion equation
    865.20 : 1,297.62 = 378.12 : x
  2. Step 2: Convert to fraction form
    865.20/1,297.62 = 378.12/x
  3. Step 3: Cross multiply
    865.20x = 1,297.62 × 378.12
  4. Step 4: Simplify right side
    865.20x = 490,656.07
  5. Step 5: Solve for x
    x = 490,656.07/865.20
  6. Step 6: Final answer
    x = 567.10

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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.