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Finding the Fourth Proportional to 84.80, 126.60 and 74.72

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Solution

The fourth proportional to 84.80, 126.60 and 74.72 is: 111.55

Step by Step Solution

  1. Step 1: Write the proportion equation
    84.80 : 126.60 = 74.72 : x
  2. Step 2: Convert to fraction form
    84.80/126.60 = 74.72/x
  3. Step 3: Cross multiply
    84.80x = 126.60 × 74.72
  4. Step 4: Simplify right side
    84.80x = 9,459.55
  5. Step 5: Solve for x
    x = 9,459.55/84.80
  6. Step 6: Final answer
    x = 111.55

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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.