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Finding the Fourth Proportional to 421.28, 631.22 and 256.66

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Solution

The fourth proportional to 421.28, 631.22 and 256.66 is: 384.56

Step by Step Solution

  1. Step 1: Write the proportion equation
    421.28 : 631.22 = 256.66 : x
  2. Step 2: Convert to fraction form
    421.28/631.22 = 256.66/x
  3. Step 3: Cross multiply
    421.28x = 631.22 × 256.66
  4. Step 4: Simplify right side
    421.28x = 162,008.93
  5. Step 5: Solve for x
    x = 162,008.93/421.28
  6. Step 6: Final answer
    x = 384.56

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Why These Related Problems?

These problems maintain the same ratio (1.50) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.