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Finding the Fourth Proportional to 1,121.55, 1,682.73 and 390.69

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Solution

The fourth proportional to 1,121.55, 1,682.73 and 390.69 is: 586.18

Step by Step Solution

  1. Step 1: Write the proportion equation
    1,121.55 : 1,682.73 = 390.69 : x
  2. Step 2: Convert to fraction form
    1,121.55/1,682.73 = 390.69/x
  3. Step 3: Cross multiply
    1,121.55x = 1,682.73 × 390.69
  4. Step 4: Simplify right side
    1,121.55x = 657,425.78
  5. Step 5: Solve for x
    x = 657,425.78/1,121.55
  6. Step 6: Final answer
    x = 586.18

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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.