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Finding the Fourth Proportional to 74.16, 111.42 and 66.78

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Solution

The fourth proportional to 74.16, 111.42 and 66.78 is: 100.33

Step by Step Solution

  1. Step 1: Write the proportion equation
    74.16 : 111.42 = 66.78 : x
  2. Step 2: Convert to fraction form
    74.16/111.42 = 66.78/x
  3. Step 3: Cross multiply
    74.16x = 111.42 × 66.78
  4. Step 4: Simplify right side
    74.16x = 7,440.63
  5. Step 5: Solve for x
    x = 7,440.63/74.16
  6. Step 6: Final answer
    x = 100.33

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Why These Related Problems?

These problems maintain the same ratio (1.50) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.