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Finding the Fourth Proportional to 205.21, 283.13 and 139.78

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Solution

The fourth proportional to 205.21, 283.13 and 139.78 is: 192.85

Step by Step Solution

  1. Step 1: Write the proportion equation
    205.21 : 283.13 = 139.78 : x
  2. Step 2: Convert to fraction form
    205.21/283.13 = 139.78/x
  3. Step 3: Cross multiply
    205.21x = 283.13 × 139.78
  4. Step 4: Simplify right side
    205.21x = 39,574.50
  5. Step 5: Solve for x
    x = 39,574.50/205.21
  6. Step 6: Final answer
    x = 192.85

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Why These Related Problems?

These problems maintain the same ratio (1.38) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.