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Finding the Fourth Proportional to 84.51, 126.81 and 54.18

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Solution

The fourth proportional to 84.51, 126.81 and 54.18 is: 81.30

Step by Step Solution

  1. Step 1: Write the proportion equation
    84.51 : 126.81 = 54.18 : x
  2. Step 2: Convert to fraction form
    84.51/126.81 = 54.18/x
  3. Step 3: Cross multiply
    84.51x = 126.81 × 54.18
  4. Step 4: Simplify right side
    84.51x = 6,870.57
  5. Step 5: Solve for x
    x = 6,870.57/84.51
  6. Step 6: Final answer
    x = 81.30

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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.