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Finding the Fourth Proportional to 209.48, 313.74 and 128.18

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Solution

The fourth proportional to 209.48, 313.74 and 128.18 is: 191.98

Step by Step Solution

  1. Step 1: Write the proportion equation
    209.48 : 313.74 = 128.18 : x
  2. Step 2: Convert to fraction form
    209.48/313.74 = 128.18/x
  3. Step 3: Cross multiply
    209.48x = 313.74 × 128.18
  4. Step 4: Simplify right side
    209.48x = 40,215.19
  5. Step 5: Solve for x
    x = 40,215.19/209.48
  6. Step 6: Final answer
    x = 191.98

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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.