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Finding the Fourth Proportional to 721.47, 1,081.55 and 259.14

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Solution

The fourth proportional to 721.47, 1,081.55 and 259.14 is: 388.47

Step by Step Solution

  1. Step 1: Write the proportion equation
    721.47 : 1,081.55 = 259.14 : x
  2. Step 2: Convert to fraction form
    721.47/1,081.55 = 259.14/x
  3. Step 3: Cross multiply
    721.47x = 1,081.55 × 259.14
  4. Step 4: Simplify right side
    721.47x = 280,268.97
  5. Step 5: Solve for x
    x = 280,268.97/721.47
  6. Step 6: Final answer
    x = 388.47

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Double scale
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1.5x scale

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.