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Finding the Fourth Proportional to 1,310.90, 1,809.05 and 721.53

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Solution

The fourth proportional to 1,310.90, 1,809.05 and 721.53 is: 995.72

Step by Step Solution

  1. Step 1: Write the proportion equation
    1,310.90 : 1,809.05 = 721.53 : x
  2. Step 2: Convert to fraction form
    1,310.90/1,809.05 = 721.53/x
  3. Step 3: Cross multiply
    1,310.90x = 1,809.05 × 721.53
  4. Step 4: Simplify right side
    1,310.90x = 1,305,280.24
  5. Step 5: Solve for x
    x = 1,305,280.24/1,310.90
  6. Step 6: Final answer
    x = 995.72

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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.