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Finding the Fourth Proportional to 1,285.90, 1,928.12 and 408.23

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Solution

The fourth proportional to 1,285.90, 1,928.12 and 408.23 is: 612.11

Step by Step Solution

  1. Step 1: Write the proportion equation
    1,285.90 : 1,928.12 = 408.23 : x
  2. Step 2: Convert to fraction form
    1,285.90/1,928.12 = 408.23/x
  3. Step 3: Cross multiply
    1,285.90x = 1,928.12 × 408.23
  4. Step 4: Simplify right side
    1,285.90x = 787,114.39
  5. Step 5: Solve for x
    x = 787,114.39/1,285.90
  6. Step 6: Final answer
    x = 612.11

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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.