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Finding the Fourth Proportional to 205.90, 309 and 84.16

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Solution

The fourth proportional to 205.90, 309 and 84.16 is: 126.30

Step by Step Solution

  1. Step 1: Write the proportion equation
    205.90 : 309 = 84.16 : x
  2. Step 2: Convert to fraction form
    205.90/309 = 84.16/x
  3. Step 3: Cross multiply
    205.90x = 309 × 84.16
  4. Step 4: Simplify right side
    205.90x = 26,005.44
  5. Step 5: Solve for x
    x = 26,005.44/205.90
  6. Step 6: Final answer
    x = 126.30

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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.