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Finding the Fourth Proportional to 855.15, 1,280.57 and 809.79

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Solution

The fourth proportional to 855.15, 1,280.57 and 809.79 is: 1,212.64

Step by Step Solution

  1. Step 1: Write the proportion equation
    855.15 : 1,280.57 = 809.79 : x
  2. Step 2: Convert to fraction form
    855.15/1,280.57 = 809.79/x
  3. Step 3: Cross multiply
    855.15x = 1,280.57 × 809.79
  4. Step 4: Simplify right side
    855.15x = 1,036,988.73
  5. Step 5: Solve for x
    x = 1,036,988.73/855.15
  6. Step 6: Final answer
    x = 1,212.64

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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.