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Finding the Fourth Proportional to 426.65, 639.99 and 138.11

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Solution

The fourth proportional to 426.65, 639.99 and 138.11 is: 207.16

Step by Step Solution

  1. Step 1: Write the proportion equation
    426.65 : 639.99 = 138.11 : x
  2. Step 2: Convert to fraction form
    426.65/639.99 = 138.11/x
  3. Step 3: Cross multiply
    426.65x = 639.99 × 138.11
  4. Step 4: Simplify right side
    426.65x = 88,385.82
  5. Step 5: Solve for x
    x = 88,385.82/426.65
  6. Step 6: Final answer
    x = 207.16

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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.