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Finding the Fourth Proportional to 81.60, 123.01 and 77.75

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Solution

The fourth proportional to 81.60, 123.01 and 77.75 is: 117.21

Step by Step Solution

  1. Step 1: Write the proportion equation
    81.60 : 123.01 = 77.75 : x
  2. Step 2: Convert to fraction form
    81.60/123.01 = 77.75/x
  3. Step 3: Cross multiply
    81.60x = 123.01 × 77.75
  4. Step 4: Simplify right side
    81.60x = 9,564.03
  5. Step 5: Solve for x
    x = 9,564.03/81.60
  6. Step 6: Final answer
    x = 117.21

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Why These Related Problems?

These problems maintain the same ratio (1.51) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.