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Finding the Fourth Proportional to 428.77, 642.85 and 265.96

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Solution

The fourth proportional to 428.77, 642.85 and 265.96 is: 398.75

Step by Step Solution

  1. Step 1: Write the proportion equation
    428.77 : 642.85 = 265.96 : x
  2. Step 2: Convert to fraction form
    428.77/642.85 = 265.96/x
  3. Step 3: Cross multiply
    428.77x = 642.85 × 265.96
  4. Step 4: Simplify right side
    428.77x = 170,970.11
  5. Step 5: Solve for x
    x = 170,970.11/428.77
  6. Step 6: Final answer
    x = 398.75

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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.