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Finding the Fourth Proportional to 42.80, 64.20 and 12.37

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Solution

The fourth proportional to 42.80, 64.20 and 12.37 is: 18.55

Step by Step Solution

  1. Step 1: Write the proportion equation
    42.80 : 64.20 = 12.37 : x
  2. Step 2: Convert to fraction form
    42.80/64.20 = 12.37/x
  3. Step 3: Cross multiply
    42.80x = 64.20 × 12.37
  4. Step 4: Simplify right side
    42.80x = 793.83
  5. Step 5: Solve for x
    x = 793.83/42.80
  6. Step 6: Final answer
    x = 18.55

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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.