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Finding the Fourth Proportional to 1,239.27, 1,856.51 and 689.79

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Solution

The fourth proportional to 1,239.27, 1,856.51 and 689.79 is: 1,033.35

Step by Step Solution

  1. Step 1: Write the proportion equation
    1,239.27 : 1,856.51 = 689.79 : x
  2. Step 2: Convert to fraction form
    1,239.27/1,856.51 = 689.79/x
  3. Step 3: Cross multiply
    1,239.27x = 1,856.51 × 689.79
  4. Step 4: Simplify right side
    1,239.27x = 1,280,602.03
  5. Step 5: Solve for x
    x = 1,280,602.03/1,239.27
  6. Step 6: Final answer
    x = 1,033.35

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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.