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Finding the Fourth Proportional to 209.17, 313.63 and 85.73

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Solution

The fourth proportional to 209.17, 313.63 and 85.73 is: 128.55

Step by Step Solution

  1. Step 1: Write the proportion equation
    209.17 : 313.63 = 85.73 : x
  2. Step 2: Convert to fraction form
    209.17/313.63 = 85.73/x
  3. Step 3: Cross multiply
    209.17x = 313.63 × 85.73
  4. Step 4: Simplify right side
    209.17x = 26,888.07
  5. Step 5: Solve for x
    x = 26,888.07/209.17
  6. Step 6: Final answer
    x = 128.55

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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.