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Finding the Fourth Proportional to 74.79, 103.12 and 66.15

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Solution

The fourth proportional to 74.79, 103.12 and 66.15 is: 91.21

Step by Step Solution

  1. Step 1: Write the proportion equation
    74.79 : 103.12 = 66.15 : x
  2. Step 2: Convert to fraction form
    74.79/103.12 = 66.15/x
  3. Step 3: Cross multiply
    74.79x = 103.12 × 66.15
  4. Step 4: Simplify right side
    74.79x = 6,821.39
  5. Step 5: Solve for x
    x = 6,821.39/74.79
  6. Step 6: Final answer
    x = 91.21

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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.