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Finding the Fourth Proportional to 387.78, 535.16 and 213.12

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Solution

The fourth proportional to 387.78, 535.16 and 213.12 is: 294.12

Step by Step Solution

  1. Step 1: Write the proportion equation
    387.78 : 535.16 = 213.12 : x
  2. Step 2: Convert to fraction form
    387.78/535.16 = 213.12/x
  3. Step 3: Cross multiply
    387.78x = 535.16 × 213.12
  4. Step 4: Simplify right side
    387.78x = 114,053.30
  5. Step 5: Solve for x
    x = 114,053.30/387.78
  6. Step 6: Final answer
    x = 294.12

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Why These Related Problems?

These problems maintain the same ratio (1.38) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.