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Finding the Fourth Proportional to 387, 534 and 221.20

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Solution

The fourth proportional to 387, 534 and 221.20 is: 305.22

Step by Step Solution

  1. Step 1: Write the proportion equation
    387 : 534 = 221.20 : x
  2. Step 2: Convert to fraction form
    387/534 = 221.20/x
  3. Step 3: Cross multiply
    387x = 534 × 221.20
  4. Step 4: Simplify right side
    387x = 118,120.80
  5. Step 5: Solve for x
    x = 118,120.80/387
  6. Step 6: Final answer
    x = 305.22

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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.