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Finding the Fourth Proportional to 1,280.66, 1,767.17 and 721.11

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Solution

The fourth proportional to 1,280.66, 1,767.17 and 721.11 is: 995.05

Step by Step Solution

  1. Step 1: Write the proportion equation
    1,280.66 : 1,767.17 = 721.11 : x
  2. Step 2: Convert to fraction form
    1,280.66/1,767.17 = 721.11/x
  3. Step 3: Cross multiply
    1,280.66x = 1,767.17 × 721.11
  4. Step 4: Simplify right side
    1,280.66x = 1,274,320.35
  5. Step 5: Solve for x
    x = 1,274,320.35/1,280.66
  6. Step 6: Final answer
    x = 995.05

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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.