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Finding the Fourth Proportional to 428, 642.08 and 254.58

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Solution

The fourth proportional to 428, 642.08 and 254.58 is: 381.92

Step by Step Solution

  1. Step 1: Write the proportion equation
    428 : 642.08 = 254.58 : x
  2. Step 2: Convert to fraction form
    428/642.08 = 254.58/x
  3. Step 3: Cross multiply
    428x = 642.08 × 254.58
  4. Step 4: Simplify right side
    428x = 163,460.73
  5. Step 5: Solve for x
    x = 163,460.73/428
  6. Step 6: Final answer
    x = 381.92

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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.