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Finding the Fourth Proportional to 205.21, 307.68 and 81.77

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Solution

The fourth proportional to 205.21, 307.68 and 81.77 is: 122.60

Step by Step Solution

  1. Step 1: Write the proportion equation
    205.21 : 307.68 = 81.77 : x
  2. Step 2: Convert to fraction form
    205.21/307.68 = 81.77/x
  3. Step 3: Cross multiply
    205.21x = 307.68 × 81.77
  4. Step 4: Simplify right side
    205.21x = 25,158.99
  5. Step 5: Solve for x
    x = 25,158.99/205.21
  6. Step 6: Final answer
    x = 122.60

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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.