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Finding the Fourth Proportional to 42.92, 64.40 and 20.07

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Solution

The fourth proportional to 42.92, 64.40 and 20.07 is: 30.12

Step by Step Solution

  1. Step 1: Write the proportion equation
    42.92 : 64.40 = 20.07 : x
  2. Step 2: Convert to fraction form
    42.92/64.40 = 20.07/x
  3. Step 3: Cross multiply
    42.92x = 64.40 × 20.07
  4. Step 4: Simplify right side
    42.92x = 1,292.41
  5. Step 5: Solve for x
    x = 1,292.41/42.92
  6. Step 6: Final answer
    x = 30.12

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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.