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Finding the Fourth Proportional to 1,238.68, 1,856.79 and 690.58

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Solution

The fourth proportional to 1,238.68, 1,856.79 and 690.58 is: 1,035.18

Step by Step Solution

  1. Step 1: Write the proportion equation
    1,238.68 : 1,856.79 = 690.58 : x
  2. Step 2: Convert to fraction form
    1,238.68/1,856.79 = 690.58/x
  3. Step 3: Cross multiply
    1,238.68x = 1,856.79 × 690.58
  4. Step 4: Simplify right side
    1,238.68x = 1,282,262.04
  5. Step 5: Solve for x
    x = 1,282,262.04/1,238.68
  6. Step 6: Final answer
    x = 1,035.18

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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.