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Finding the Fourth Proportional to 84.95, 126.53 and 81

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Solution

The fourth proportional to 84.95, 126.53 and 81 is: 120.65

Step by Step Solution

  1. Step 1: Write the proportion equation
    84.95 : 126.53 = 81 : x
  2. Step 2: Convert to fraction form
    84.95/126.53 = 81/x
  3. Step 3: Cross multiply
    84.95x = 126.53 × 81
  4. Step 4: Simplify right side
    84.95x = 10,248.93
  5. Step 5: Solve for x
    x = 10,248.93/84.95
  6. Step 6: Final answer
    x = 120.65

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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.