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Finding the Fourth Proportional to 209.17, 313.30 and 128.08

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Solution

The fourth proportional to 209.17, 313.30 and 128.08 is: 191.84

Step by Step Solution

  1. Step 1: Write the proportion equation
    209.17 : 313.30 = 128.08 : x
  2. Step 2: Convert to fraction form
    209.17/313.30 = 128.08/x
  3. Step 3: Cross multiply
    209.17x = 313.30 × 128.08
  4. Step 4: Simplify right side
    209.17x = 40,127.46
  5. Step 5: Solve for x
    x = 40,127.46/209.17
  6. Step 6: Final answer
    x = 191.84

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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.