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Finding the Fourth Proportional to 84.51, 126.78 and 38.85

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Solution

The fourth proportional to 84.51, 126.78 and 38.85 is: 58.28

Step by Step Solution

  1. Step 1: Write the proportion equation
    84.51 : 126.78 = 38.85 : x
  2. Step 2: Convert to fraction form
    84.51/126.78 = 38.85/x
  3. Step 3: Cross multiply
    84.51x = 126.78 × 38.85
  4. Step 4: Simplify right side
    84.51x = 4,925.40
  5. Step 5: Solve for x
    x = 4,925.40/84.51
  6. Step 6: Final answer
    x = 58.28

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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.