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Finding the Fourth Proportional to 57.17, 78.90 and 31.30

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Solution

The fourth proportional to 57.17, 78.90 and 31.30 is: 43.19

Step by Step Solution

  1. Step 1: Write the proportion equation
    57.17 : 78.90 = 31.30 : x
  2. Step 2: Convert to fraction form
    57.17/78.90 = 31.30/x
  3. Step 3: Cross multiply
    57.17x = 78.90 × 31.30
  4. Step 4: Simplify right side
    57.17x = 2,469.02
  5. Step 5: Solve for x
    x = 2,469.02/57.17
  6. Step 6: Final answer
    x = 43.19

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Why These Related Problems?

These problems maintain the same ratio (1.38) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.