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Finding the Fourth Proportional to 71.78, 98.88 and 68.12

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Solution

The fourth proportional to 71.78, 98.88 and 68.12 is: 93.84

Step by Step Solution

  1. Step 1: Write the proportion equation
    71.78 : 98.88 = 68.12 : x
  2. Step 2: Convert to fraction form
    71.78/98.88 = 68.12/x
  3. Step 3: Cross multiply
    71.78x = 98.88 × 68.12
  4. Step 4: Simplify right side
    71.78x = 6,735.71
  5. Step 5: Solve for x
    x = 6,735.71/71.78
  6. Step 6: Final answer
    x = 93.84

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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.