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Finding the Fourth Proportional to 74.58, 103.08 and 65.78

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Solution

The fourth proportional to 74.58, 103.08 and 65.78 is: 90.91

Step by Step Solution

  1. Step 1: Write the proportion equation
    74.58 : 103.08 = 65.78 : x
  2. Step 2: Convert to fraction form
    74.58/103.08 = 65.78/x
  3. Step 3: Cross multiply
    74.58x = 103.08 × 65.78
  4. Step 4: Simplify right side
    74.58x = 6,780.33
  5. Step 5: Solve for x
    x = 6,780.33/74.58
  6. Step 6: Final answer
    x = 90.91

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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.