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Finding the Fourth Proportional to 1,238.65, 1,858.03 and 690.42

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Solution

The fourth proportional to 1,238.65, 1,858.03 and 690.42 is: 1,035.66

Step by Step Solution

  1. Step 1: Write the proportion equation
    1,238.65 : 1,858.03 = 690.42 : x
  2. Step 2: Convert to fraction form
    1,238.65/1,858.03 = 690.42/x
  3. Step 3: Cross multiply
    1,238.65x = 1,858.03 × 690.42
  4. Step 4: Simplify right side
    1,238.65x = 1,282,821.07
  5. Step 5: Solve for x
    x = 1,282,821.07/1,238.65
  6. Step 6: Final answer
    x = 1,035.66

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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.