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Finding the Fourth Proportional to 121.64, 182.39 and 86.91

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Solution

The fourth proportional to 121.64, 182.39 and 86.91 is: 130.32

Step by Step Solution

  1. Step 1: Write the proportion equation
    121.64 : 182.39 = 86.91 : x
  2. Step 2: Convert to fraction form
    121.64/182.39 = 86.91/x
  3. Step 3: Cross multiply
    121.64x = 182.39 × 86.91
  4. Step 4: Simplify right side
    121.64x = 15,851.73
  5. Step 5: Solve for x
    x = 15,851.73/121.64
  6. Step 6: Final answer
    x = 130.32

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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.