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Finding the Fourth Proportional to 281.08, 421.74 and 257.20

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Solution

The fourth proportional to 281.08, 421.74 and 257.20 is: 385.91

Step by Step Solution

  1. Step 1: Write the proportion equation
    281.08 : 421.74 = 257.20 : x
  2. Step 2: Convert to fraction form
    281.08/421.74 = 257.20/x
  3. Step 3: Cross multiply
    281.08x = 421.74 × 257.20
  4. Step 4: Simplify right side
    281.08x = 108,471.53
  5. Step 5: Solve for x
    x = 108,471.53/281.08
  6. Step 6: Final answer
    x = 385.91

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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.