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Finding the Fourth Proportional to 1,280.16, 1,919.64 and 811.76

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Solution

The fourth proportional to 1,280.16, 1,919.64 and 811.76 is: 1,217.26

Step by Step Solution

  1. Step 1: Write the proportion equation
    1,280.16 : 1,919.64 = 811.76 : x
  2. Step 2: Convert to fraction form
    1,280.16/1,919.64 = 811.76/x
  3. Step 3: Cross multiply
    1,280.16x = 1,919.64 × 811.76
  4. Step 4: Simplify right side
    1,280.16x = 1,558,286.97
  5. Step 5: Solve for x
    x = 1,558,286.97/1,280.16
  6. Step 6: Final answer
    x = 1,217.26

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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.