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Finding the Fourth Proportional to 121.16, 181.56 and 90.68

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Solution

The fourth proportional to 121.16, 181.56 and 90.68 is: 135.89

Step by Step Solution

  1. Step 1: Write the proportion equation
    121.16 : 181.56 = 90.68 : x
  2. Step 2: Convert to fraction form
    121.16/181.56 = 90.68/x
  3. Step 3: Cross multiply
    121.16x = 181.56 × 90.68
  4. Step 4: Simplify right side
    121.16x = 16,463.86
  5. Step 5: Solve for x
    x = 16,463.86/121.16
  6. Step 6: Final answer
    x = 135.89

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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.