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Finding the Fourth Proportional to 108.40, 149.49 and 87.67

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Solution

The fourth proportional to 108.40, 149.49 and 87.67 is: 120.90

Step by Step Solution

  1. Step 1: Write the proportion equation
    108.40 : 149.49 = 87.67 : x
  2. Step 2: Convert to fraction form
    108.40/149.49 = 87.67/x
  3. Step 3: Cross multiply
    108.40x = 149.49 × 87.67
  4. Step 4: Simplify right side
    108.40x = 13,105.79
  5. Step 5: Solve for x
    x = 13,105.79/108.40
  6. Step 6: Final answer
    x = 120.90

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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.