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Finding the Fourth Proportional to 920.39, 1,380.60 and 407.39

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Solution

The fourth proportional to 920.39, 1,380.60 and 407.39 is: 611.09

Step by Step Solution

  1. Step 1: Write the proportion equation
    920.39 : 1,380.60 = 407.39 : x
  2. Step 2: Convert to fraction form
    920.39/1,380.60 = 407.39/x
  3. Step 3: Cross multiply
    920.39x = 1,380.60 × 407.39
  4. Step 4: Simplify right side
    920.39x = 562,442.63
  5. Step 5: Solve for x
    x = 562,442.63/920.39
  6. Step 6: Final answer
    x = 611.09

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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.