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Finding the Fourth Proportional to 431.78, 647.82 and 215.24

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Solution

The fourth proportional to 431.78, 647.82 and 215.24 is: 322.93

Step by Step Solution

  1. Step 1: Write the proportion equation
    431.78 : 647.82 = 215.24 : x
  2. Step 2: Convert to fraction form
    431.78/647.82 = 215.24/x
  3. Step 3: Cross multiply
    431.78x = 647.82 × 215.24
  4. Step 4: Simplify right side
    431.78x = 139,433.54
  5. Step 5: Solve for x
    x = 139,433.54/431.78
  6. Step 6: Final answer
    x = 322.93

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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.