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Finding the Fourth Proportional to 387.79, 535.13 and 221.98

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Solution

The fourth proportional to 387.79, 535.13 and 221.98 is: 306.32

Step by Step Solution

  1. Step 1: Write the proportion equation
    387.79 : 535.13 = 221.98 : x
  2. Step 2: Convert to fraction form
    387.79/535.13 = 221.98/x
  3. Step 3: Cross multiply
    387.79x = 535.13 × 221.98
  4. Step 4: Simplify right side
    387.79x = 118,788.16
  5. Step 5: Solve for x
    x = 118,788.16/387.79
  6. Step 6: Final answer
    x = 306.32

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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.