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Finding the Fourth Proportional to 920.81, 1,381.31 and 343.55

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Solution

The fourth proportional to 920.81, 1,381.31 and 343.55 is: 515.36

Step by Step Solution

  1. Step 1: Write the proportion equation
    920.81 : 1,381.31 = 343.55 : x
  2. Step 2: Convert to fraction form
    920.81/1,381.31 = 343.55/x
  3. Step 3: Cross multiply
    920.81x = 1,381.31 × 343.55
  4. Step 4: Simplify right side
    920.81x = 474,549.05
  5. Step 5: Solve for x
    x = 474,549.05/920.81
  6. Step 6: Final answer
    x = 515.36

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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.