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Finding the Fourth Proportional to 74.58, 102.45 and 66.90

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Solution

The fourth proportional to 74.58, 102.45 and 66.90 is: 91.90

Step by Step Solution

  1. Step 1: Write the proportion equation
    74.58 : 102.45 = 66.90 : x
  2. Step 2: Convert to fraction form
    74.58/102.45 = 66.90/x
  3. Step 3: Cross multiply
    74.58x = 102.45 × 66.90
  4. Step 4: Simplify right side
    74.58x = 6,853.91
  5. Step 5: Solve for x
    x = 6,853.91/74.58
  6. Step 6: Final answer
    x = 91.90

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Why These Related Problems?

These problems maintain the same ratio (1.37) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.