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Finding the Fourth Proportional to 1,290.28, 1,780.61 and 759.20

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Solution

The fourth proportional to 1,290.28, 1,780.61 and 759.20 is: 1,047.71

Step by Step Solution

  1. Step 1: Write the proportion equation
    1,290.28 : 1,780.61 = 759.20 : x
  2. Step 2: Convert to fraction form
    1,290.28/1,780.61 = 759.20/x
  3. Step 3: Cross multiply
    1,290.28x = 1,780.61 × 759.20
  4. Step 4: Simplify right side
    1,290.28x = 1,351,832.11
  5. Step 5: Solve for x
    x = 1,351,832.11/1,290.28
  6. Step 6: Final answer
    x = 1,047.71

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Why These Related Problems?

These problems maintain the same ratio (1.38) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.