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Finding the Fourth Proportional to 74.78, 102.90 and 67.88

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Solution

The fourth proportional to 74.78, 102.90 and 67.88 is: 93.41

Step by Step Solution

  1. Step 1: Write the proportion equation
    74.78 : 102.90 = 67.88 : x
  2. Step 2: Convert to fraction form
    74.78/102.90 = 67.88/x
  3. Step 3: Cross multiply
    74.78x = 102.90 × 67.88
  4. Step 4: Simplify right side
    74.78x = 6,984.85
  5. Step 5: Solve for x
    x = 6,984.85/74.78
  6. Step 6: Final answer
    x = 93.41

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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.