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Finding the Fourth Proportional to 120.86, 180.92 and 90.50

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Solution

The fourth proportional to 120.86, 180.92 and 90.50 is: 135.47

Step by Step Solution

  1. Step 1: Write the proportion equation
    120.86 : 180.92 = 90.50 : x
  2. Step 2: Convert to fraction form
    120.86/180.92 = 90.50/x
  3. Step 3: Cross multiply
    120.86x = 180.92 × 90.50
  4. Step 4: Simplify right side
    120.86x = 16,373.26
  5. Step 5: Solve for x
    x = 16,373.26/120.86
  6. Step 6: Final answer
    x = 135.47

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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.