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Finding the Fourth Proportional to 1,439.78, 2,159.89 and 515.12

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Solution

The fourth proportional to 1,439.78, 2,159.89 and 515.12 is: 772.76

Step by Step Solution

  1. Step 1: Write the proportion equation
    1,439.78 : 2,159.89 = 515.12 : x
  2. Step 2: Convert to fraction form
    1,439.78/2,159.89 = 515.12/x
  3. Step 3: Cross multiply
    1,439.78x = 2,159.89 × 515.12
  4. Step 4: Simplify right side
    1,439.78x = 1,112,606.65
  5. Step 5: Solve for x
    x = 1,112,606.65/1,439.78
  6. Step 6: Final answer
    x = 772.76

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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.