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Finding the Fourth Proportional to 428.95, 642.79 and 320.68

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Solution

The fourth proportional to 428.95, 642.79 and 320.68 is: 480.55

Step by Step Solution

  1. Step 1: Write the proportion equation
    428.95 : 642.79 = 320.68 : x
  2. Step 2: Convert to fraction form
    428.95/642.79 = 320.68/x
  3. Step 3: Cross multiply
    428.95x = 642.79 × 320.68
  4. Step 4: Simplify right side
    428.95x = 206,129.90
  5. Step 5: Solve for x
    x = 206,129.90/428.95
  6. Step 6: Final answer
    x = 480.55

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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.