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Finding the Fourth Proportional to 428.33, 642.50 and 120.21

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Solution

The fourth proportional to 428.33, 642.50 and 120.21 is: 180.32

Step by Step Solution

  1. Step 1: Write the proportion equation
    428.33 : 642.50 = 120.21 : x
  2. Step 2: Convert to fraction form
    428.33/642.50 = 120.21/x
  3. Step 3: Cross multiply
    428.33x = 642.50 × 120.21
  4. Step 4: Simplify right side
    428.33x = 77,234.93
  5. Step 5: Solve for x
    x = 77,234.93/428.33
  6. Step 6: Final answer
    x = 180.32

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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.