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Finding the Fourth Proportional to 108.66, 149.78 and 87.86

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Solution

The fourth proportional to 108.66, 149.78 and 87.86 is: 121.11

Step by Step Solution

  1. Step 1: Write the proportion equation
    108.66 : 149.78 = 87.86 : x
  2. Step 2: Convert to fraction form
    108.66/149.78 = 87.86/x
  3. Step 3: Cross multiply
    108.66x = 149.78 × 87.86
  4. Step 4: Simplify right side
    108.66x = 13,159.67
  5. Step 5: Solve for x
    x = 13,159.67/108.66
  6. Step 6: Final answer
    x = 121.11

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Why These Related Problems?

These problems maintain the same ratio (1.38) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.