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Finding the Fourth Proportional to 1,238.57, 1,857.90 and 690.35

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Solution

The fourth proportional to 1,238.57, 1,857.90 and 690.35 is: 1,035.55

Step by Step Solution

  1. Step 1: Write the proportion equation
    1,238.57 : 1,857.90 = 690.35 : x
  2. Step 2: Convert to fraction form
    1,238.57/1,857.90 = 690.35/x
  3. Step 3: Cross multiply
    1,238.57x = 1,857.90 × 690.35
  4. Step 4: Simplify right side
    1,238.57x = 1,282,591.98
  5. Step 5: Solve for x
    x = 1,282,591.98/1,238.57
  6. Step 6: Final answer
    x = 1,035.55

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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.