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Finding the Fourth Proportional to 865.88, 1,298.40 and 427.18

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Solution

The fourth proportional to 865.88, 1,298.40 and 427.18 is: 640.56

Step by Step Solution

  1. Step 1: Write the proportion equation
    865.88 : 1,298.40 = 427.18 : x
  2. Step 2: Convert to fraction form
    865.88/1,298.40 = 427.18/x
  3. Step 3: Cross multiply
    865.88x = 1,298.40 × 427.18
  4. Step 4: Simplify right side
    865.88x = 554,650.51
  5. Step 5: Solve for x
    x = 554,650.51/865.88
  6. Step 6: Final answer
    x = 640.56

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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.