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Finding the Fourth Proportional to 74.79, 111.60 and 66.15

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Solution

The fourth proportional to 74.79, 111.60 and 66.15 is: 98.71

Step by Step Solution

  1. Step 1: Write the proportion equation
    74.79 : 111.60 = 66.15 : x
  2. Step 2: Convert to fraction form
    74.79/111.60 = 66.15/x
  3. Step 3: Cross multiply
    74.79x = 111.60 × 66.15
  4. Step 4: Simplify right side
    74.79x = 7,382.34
  5. Step 5: Solve for x
    x = 7,382.34/74.79
  6. Step 6: Final answer
    x = 98.71

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Why These Related Problems?

These problems maintain the same ratio (1.49) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.