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Finding the Fourth Proportional to 1,280.60, 1,767.18 and 721.09

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Solution

The fourth proportional to 1,280.60, 1,767.18 and 721.09 is: 995.08

Step by Step Solution

  1. Step 1: Write the proportion equation
    1,280.60 : 1,767.18 = 721.09 : x
  2. Step 2: Convert to fraction form
    1,280.60/1,767.18 = 721.09/x
  3. Step 3: Cross multiply
    1,280.60x = 1,767.18 × 721.09
  4. Step 4: Simplify right side
    1,280.60x = 1,274,295.83
  5. Step 5: Solve for x
    x = 1,274,295.83/1,280.60
  6. Step 6: Final answer
    x = 995.08

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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.