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Finding the Fourth Proportional to 81.58, 121.31 and 79.01

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Solution

The fourth proportional to 81.58, 121.31 and 79.01 is: 117.50

Step by Step Solution

  1. Step 1: Write the proportion equation
    81.58 : 121.31 = 79.01 : x
  2. Step 2: Convert to fraction form
    81.58/121.31 = 79.01/x
  3. Step 3: Cross multiply
    81.58x = 121.31 × 79.01
  4. Step 4: Simplify right side
    81.58x = 9,584.70
  5. Step 5: Solve for x
    x = 9,584.70/81.58
  6. Step 6: Final answer
    x = 117.50

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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.