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Finding the Fourth Proportional to 809.56, 1,115.22 and 780.76

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Solution

The fourth proportional to 809.56, 1,115.22 and 780.76 is: 1,075.55

Step by Step Solution

  1. Step 1: Write the proportion equation
    809.56 : 1,115.22 = 780.76 : x
  2. Step 2: Convert to fraction form
    809.56/1,115.22 = 780.76/x
  3. Step 3: Cross multiply
    809.56x = 1,115.22 × 780.76
  4. Step 4: Simplify right side
    809.56x = 870,719.17
  5. Step 5: Solve for x
    x = 870,719.17/809.56
  6. Step 6: Final answer
    x = 1,075.55

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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.