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Finding the Fourth Proportional to 68.16, 102.12 and 31.56

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Solution

The fourth proportional to 68.16, 102.12 and 31.56 is: 47.28

Step by Step Solution

  1. Step 1: Write the proportion equation
    68.16 : 102.12 = 31.56 : x
  2. Step 2: Convert to fraction form
    68.16/102.12 = 31.56/x
  3. Step 3: Cross multiply
    68.16x = 102.12 × 31.56
  4. Step 4: Simplify right side
    68.16x = 3,222.91
  5. Step 5: Solve for x
    x = 3,222.91/68.16
  6. Step 6: Final answer
    x = 47.28

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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.