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Finding the Fourth Proportional to 920.10, 1,378.98 and 399.48

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Solution

The fourth proportional to 920.10, 1,378.98 and 399.48 is: 598.71

Step by Step Solution

  1. Step 1: Write the proportion equation
    920.10 : 1,378.98 = 399.48 : x
  2. Step 2: Convert to fraction form
    920.10/1,378.98 = 399.48/x
  3. Step 3: Cross multiply
    920.10x = 1,378.98 × 399.48
  4. Step 4: Simplify right side
    920.10x = 550,874.93
  5. Step 5: Solve for x
    x = 550,874.93/920.10
  6. Step 6: Final answer
    x = 598.71

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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.