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Finding the Fourth Proportional to 1,139.57, 1,709.80 and 728.59

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Solution

The fourth proportional to 1,139.57, 1,709.80 and 728.59 is: 1,093.17

Step by Step Solution

  1. Step 1: Write the proportion equation
    1,139.57 : 1,709.80 = 728.59 : x
  2. Step 2: Convert to fraction form
    1,139.57/1,709.80 = 728.59/x
  3. Step 3: Cross multiply
    1,139.57x = 1,709.80 × 728.59
  4. Step 4: Simplify right side
    1,139.57x = 1,245,743.18
  5. Step 5: Solve for x
    x = 1,245,743.18/1,139.57
  6. Step 6: Final answer
    x = 1,093.17

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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.