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Finding the Fourth Proportional to 121.80, 182.73 and 85.80

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Solution

The fourth proportional to 121.80, 182.73 and 85.80 is: 128.72

Step by Step Solution

  1. Step 1: Write the proportion equation
    121.80 : 182.73 = 85.80 : x
  2. Step 2: Convert to fraction form
    121.80/182.73 = 85.80/x
  3. Step 3: Cross multiply
    121.80x = 182.73 × 85.80
  4. Step 4: Simplify right side
    121.80x = 15,678.23
  5. Step 5: Solve for x
    x = 15,678.23/121.80
  6. Step 6: Final answer
    x = 128.72

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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.