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Finding the Fourth Proportional to 100.19, 149.47 and 86.69

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Solution

The fourth proportional to 100.19, 149.47 and 86.69 is: 129.33

Step by Step Solution

  1. Step 1: Write the proportion equation
    100.19 : 149.47 = 86.69 : x
  2. Step 2: Convert to fraction form
    100.19/149.47 = 86.69/x
  3. Step 3: Cross multiply
    100.19x = 149.47 × 86.69
  4. Step 4: Simplify right side
    100.19x = 12,957.55
  5. Step 5: Solve for x
    x = 12,957.55/100.19
  6. Step 6: Final answer
    x = 129.33

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Why These Related Problems?

These problems maintain the same ratio (1.49) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.