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Finding the Fourth Proportional to 387.75, 535 and 221.91

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Solution

The fourth proportional to 387.75, 535 and 221.91 is: 306.18

Step by Step Solution

  1. Step 1: Write the proportion equation
    387.75 : 535 = 221.91 : x
  2. Step 2: Convert to fraction form
    387.75/535 = 221.91/x
  3. Step 3: Cross multiply
    387.75x = 535 × 221.91
  4. Step 4: Simplify right side
    387.75x = 118,721.85
  5. Step 5: Solve for x
    x = 118,721.85/387.75
  6. Step 6: Final answer
    x = 306.18

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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.