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Finding the Fourth Proportional to 205.12, 307.68 and 91.12

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Solution

The fourth proportional to 205.12, 307.68 and 91.12 is: 136.68

Step by Step Solution

  1. Step 1: Write the proportion equation
    205.12 : 307.68 = 91.12 : x
  2. Step 2: Convert to fraction form
    205.12/307.68 = 91.12/x
  3. Step 3: Cross multiply
    205.12x = 307.68 × 91.12
  4. Step 4: Simplify right side
    205.12x = 28,035.80
  5. Step 5: Solve for x
    x = 28,035.80/205.12
  6. Step 6: Final answer
    x = 136.68

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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.