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Finding the Fourth Proportional to 205.80, 308.90 and 103.20

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Solution

The fourth proportional to 205.80, 308.90 and 103.20 is: 154.90

Step by Step Solution

  1. Step 1: Write the proportion equation
    205.80 : 308.90 = 103.20 : x
  2. Step 2: Convert to fraction form
    205.80/308.90 = 103.20/x
  3. Step 3: Cross multiply
    205.80x = 308.90 × 103.20
  4. Step 4: Simplify right side
    205.80x = 31,878.48
  5. Step 5: Solve for x
    x = 31,878.48/205.80
  6. Step 6: Final answer
    x = 154.90

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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.