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Finding the Fourth Proportional to 1,280.10, 1,919.91 and 766.50

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Solution

The fourth proportional to 1,280.10, 1,919.91 and 766.50 is: 1,149.61

Step by Step Solution

  1. Step 1: Write the proportion equation
    1,280.10 : 1,919.91 = 766.50 : x
  2. Step 2: Convert to fraction form
    1,280.10/1,919.91 = 766.50/x
  3. Step 3: Cross multiply
    1,280.10x = 1,919.91 × 766.50
  4. Step 4: Simplify right side
    1,280.10x = 1,471,611.02
  5. Step 5: Solve for x
    x = 1,471,611.02/1,280.10
  6. Step 6: Final answer
    x = 1,149.61

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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.