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Finding the Fourth Proportional to 3,987.54, 5,981.31 and 1,390.47

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Solution

The fourth proportional to 3,987.54, 5,981.31 and 1,390.47 is: 2,085.71

Step by Step Solution

  1. Step 1: Write the proportion equation
    3,987.54 : 5,981.31 = 1,390.47 : x
  2. Step 2: Convert to fraction form
    3,987.54/5,981.31 = 1,390.47/x
  3. Step 3: Cross multiply
    3,987.54x = 5,981.31 × 1,390.47
  4. Step 4: Simplify right side
    3,987.54x = 8,316,832.12
  5. Step 5: Solve for x
    x = 8,316,832.12/3,987.54
  6. Step 6: Final answer
    x = 2,085.71

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Similar ratio
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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.