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Finding the Fourth Proportional to 427.02, 640.60 and 138.40

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Solution

The fourth proportional to 427.02, 640.60 and 138.40 is: 207.62

Step by Step Solution

  1. Step 1: Write the proportion equation
    427.02 : 640.60 = 138.40 : x
  2. Step 2: Convert to fraction form
    427.02/640.60 = 138.40/x
  3. Step 3: Cross multiply
    427.02x = 640.60 × 138.40
  4. Step 4: Simplify right side
    427.02x = 88,659.04
  5. Step 5: Solve for x
    x = 88,659.04/427.02
  6. Step 6: Final answer
    x = 207.62

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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.