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Finding the Fourth Proportional to 113.74, 170.39 and 86.72

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Solution

The fourth proportional to 113.74, 170.39 and 86.72 is: 129.91

Step by Step Solution

  1. Step 1: Write the proportion equation
    113.74 : 170.39 = 86.72 : x
  2. Step 2: Convert to fraction form
    113.74/170.39 = 86.72/x
  3. Step 3: Cross multiply
    113.74x = 170.39 × 86.72
  4. Step 4: Simplify right side
    113.74x = 14,776.22
  5. Step 5: Solve for x
    x = 14,776.22/113.74
  6. Step 6: Final answer
    x = 129.91

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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.