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Finding the Fourth Proportional to 42.95, 64.43 and 20.12

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Solution

The fourth proportional to 42.95, 64.43 and 20.12 is: 30.18

Step by Step Solution

  1. Step 1: Write the proportion equation
    42.95 : 64.43 = 20.12 : x
  2. Step 2: Convert to fraction form
    42.95/64.43 = 20.12/x
  3. Step 3: Cross multiply
    42.95x = 64.43 × 20.12
  4. Step 4: Simplify right side
    42.95x = 1,295.98
  5. Step 5: Solve for x
    x = 1,295.98/42.95
  6. Step 6: Final answer
    x = 30.18

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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.