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Finding the Fourth Proportional to 1,306.50, 1,959.34 and 721.28

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Solution

The fourth proportional to 1,306.50, 1,959.34 and 721.28 is: 1,081.69

Step by Step Solution

  1. Step 1: Write the proportion equation
    1,306.50 : 1,959.34 = 721.28 : x
  2. Step 2: Convert to fraction form
    1,306.50/1,959.34 = 721.28/x
  3. Step 3: Cross multiply
    1,306.50x = 1,959.34 × 721.28
  4. Step 4: Simplify right side
    1,306.50x = 1,413,232.76
  5. Step 5: Solve for x
    x = 1,413,232.76/1,306.50
  6. Step 6: Final answer
    x = 1,081.69

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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.