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Finding the Fourth Proportional to 387.78, 535.31 and 253.18

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Solution

The fourth proportional to 387.78, 535.31 and 253.18 is: 349.50

Step by Step Solution

  1. Step 1: Write the proportion equation
    387.78 : 535.31 = 253.18 : x
  2. Step 2: Convert to fraction form
    387.78/535.31 = 253.18/x
  3. Step 3: Cross multiply
    387.78x = 535.31 × 253.18
  4. Step 4: Simplify right side
    387.78x = 135,529.79
  5. Step 5: Solve for x
    x = 135,529.79/387.78
  6. Step 6: Final answer
    x = 349.50

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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.