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Finding the Fourth Proportional to 121.78, 182.57 and 72.91

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Solution

The fourth proportional to 121.78, 182.57 and 72.91 is: 109.30

Step by Step Solution

  1. Step 1: Write the proportion equation
    121.78 : 182.57 = 72.91 : x
  2. Step 2: Convert to fraction form
    121.78/182.57 = 72.91/x
  3. Step 3: Cross multiply
    121.78x = 182.57 × 72.91
  4. Step 4: Simplify right side
    121.78x = 13,310.36
  5. Step 5: Solve for x
    x = 13,310.36/121.78
  6. Step 6: Final answer
    x = 109.30

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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.