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Finding the Fourth Proportional to 205.47, 307.87 and 128.45

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Solution

The fourth proportional to 205.47, 307.87 and 128.45 is: 192.47

Step by Step Solution

  1. Step 1: Write the proportion equation
    205.47 : 307.87 = 128.45 : x
  2. Step 2: Convert to fraction form
    205.47/307.87 = 128.45/x
  3. Step 3: Cross multiply
    205.47x = 307.87 × 128.45
  4. Step 4: Simplify right side
    205.47x = 39,546.35
  5. Step 5: Solve for x
    x = 39,546.35/205.47
  6. Step 6: Final answer
    x = 192.47

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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.