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Finding the Fourth Proportional to 1,280.14, 1,919.84 and 811.30

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Solution

The fourth proportional to 1,280.14, 1,919.84 and 811.30 is: 1,216.72

Step by Step Solution

  1. Step 1: Write the proportion equation
    1,280.14 : 1,919.84 = 811.30 : x
  2. Step 2: Convert to fraction form
    1,280.14/1,919.84 = 811.30/x
  3. Step 3: Cross multiply
    1,280.14x = 1,919.84 × 811.30
  4. Step 4: Simplify right side
    1,280.14x = 1,557,566.19
  5. Step 5: Solve for x
    x = 1,557,566.19/1,280.14
  6. Step 6: Final answer
    x = 1,216.72

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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.