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Finding the Fourth Proportional to 428.82, 642.99 and 140.18

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Solution

The fourth proportional to 428.82, 642.99 and 140.18 is: 210.19

Step by Step Solution

  1. Step 1: Write the proportion equation
    428.82 : 642.99 = 140.18 : x
  2. Step 2: Convert to fraction form
    428.82/642.99 = 140.18/x
  3. Step 3: Cross multiply
    428.82x = 642.99 × 140.18
  4. Step 4: Simplify right side
    428.82x = 90,134.34
  5. Step 5: Solve for x
    x = 90,134.34/428.82
  6. Step 6: Final answer
    x = 210.19

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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.