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Finding the Fourth Proportional to 1,298.27, 1,947.11 and 639.47

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Solution

The fourth proportional to 1,298.27, 1,947.11 and 639.47 is: 959.06

Step by Step Solution

  1. Step 1: Write the proportion equation
    1,298.27 : 1,947.11 = 639.47 : x
  2. Step 2: Convert to fraction form
    1,298.27/1,947.11 = 639.47/x
  3. Step 3: Cross multiply
    1,298.27x = 1,947.11 × 639.47
  4. Step 4: Simplify right side
    1,298.27x = 1,245,120.10
  5. Step 5: Solve for x
    x = 1,245,120.10/1,298.27
  6. Step 6: Final answer
    x = 959.06

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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.