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Finding the Fourth Proportional to 690.30, 1,034.15 and 381.69

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Solution

The fourth proportional to 690.30, 1,034.15 and 381.69 is: 571.81

Step by Step Solution

  1. Step 1: Write the proportion equation
    690.30 : 1,034.15 = 381.69 : x
  2. Step 2: Convert to fraction form
    690.30/1,034.15 = 381.69/x
  3. Step 3: Cross multiply
    690.30x = 1,034.15 × 381.69
  4. Step 4: Simplify right side
    690.30x = 394,722.81
  5. Step 5: Solve for x
    x = 394,722.81/690.30
  6. Step 6: Final answer
    x = 571.81

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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.