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Finding the Fourth Proportional to 104.65, 156.78 and 91.81

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Solution

The fourth proportional to 104.65, 156.78 and 91.81 is: 137.54

Step by Step Solution

  1. Step 1: Write the proportion equation
    104.65 : 156.78 = 91.81 : x
  2. Step 2: Convert to fraction form
    104.65/156.78 = 91.81/x
  3. Step 3: Cross multiply
    104.65x = 156.78 × 91.81
  4. Step 4: Simplify right side
    104.65x = 14,393.97
  5. Step 5: Solve for x
    x = 14,393.97/104.65
  6. Step 6: Final answer
    x = 137.54

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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.