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Finding the Fourth Proportional to 209.39, 314.02 and 85.95

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Solution

The fourth proportional to 209.39, 314.02 and 85.95 is: 128.90

Step by Step Solution

  1. Step 1: Write the proportion equation
    209.39 : 314.02 = 85.95 : x
  2. Step 2: Convert to fraction form
    209.39/314.02 = 85.95/x
  3. Step 3: Cross multiply
    209.39x = 314.02 × 85.95
  4. Step 4: Simplify right side
    209.39x = 26,990.02
  5. Step 5: Solve for x
    x = 26,990.02/209.39
  6. Step 6: Final answer
    x = 128.90

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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.