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Finding the Fourth Proportional to 1,310.91, 1,809.16 and 721.55

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Solution

The fourth proportional to 1,310.91, 1,809.16 and 721.55 is: 995.80

Step by Step Solution

  1. Step 1: Write the proportion equation
    1,310.91 : 1,809.16 = 721.55 : x
  2. Step 2: Convert to fraction form
    1,310.91/1,809.16 = 721.55/x
  3. Step 3: Cross multiply
    1,310.91x = 1,809.16 × 721.55
  4. Step 4: Simplify right side
    1,310.91x = 1,305,399.40
  5. Step 5: Solve for x
    x = 1,305,399.40/1,310.91
  6. Step 6: Final answer
    x = 995.80

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1.5x scale

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.