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Finding the Fourth Proportional to 427.08, 640.60 and 138.53

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Solution

The fourth proportional to 427.08, 640.60 and 138.53 is: 207.79

Step by Step Solution

  1. Step 1: Write the proportion equation
    427.08 : 640.60 = 138.53 : x
  2. Step 2: Convert to fraction form
    427.08/640.60 = 138.53/x
  3. Step 3: Cross multiply
    427.08x = 640.60 × 138.53
  4. Step 4: Simplify right side
    427.08x = 88,742.32
  5. Step 5: Solve for x
    x = 88,742.32/427.08
  6. Step 6: Final answer
    x = 207.79

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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.