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Finding the Fourth Proportional to 421.60, 632.40 and 256.90

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Solution

The fourth proportional to 421.60, 632.40 and 256.90 is: 385.35

Step by Step Solution

  1. Step 1: Write the proportion equation
    421.60 : 632.40 = 256.90 : x
  2. Step 2: Convert to fraction form
    421.60/632.40 = 256.90/x
  3. Step 3: Cross multiply
    421.60x = 632.40 × 256.90
  4. Step 4: Simplify right side
    421.60x = 162,463.56
  5. Step 5: Solve for x
    x = 162,463.56/421.60
  6. Step 6: Final answer
    x = 385.35

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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.