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Finding the Fourth Proportional to 100.40, 149.86 and 86.96

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Solution

The fourth proportional to 100.40, 149.86 and 86.96 is: 129.80

Step by Step Solution

  1. Step 1: Write the proportion equation
    100.40 : 149.86 = 86.96 : x
  2. Step 2: Convert to fraction form
    100.40/149.86 = 86.96/x
  3. Step 3: Cross multiply
    100.40x = 149.86 × 86.96
  4. Step 4: Simplify right side
    100.40x = 13,031.83
  5. Step 5: Solve for x
    x = 13,031.83/100.40
  6. Step 6: Final answer
    x = 129.80

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