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Finding the Fourth Proportional to 1,987.78, 2,741.23 and 1,278.90

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Solution

The fourth proportional to 1,987.78, 2,741.23 and 1,278.90 is: 1,763.66

Step by Step Solution

  1. Step 1: Write the proportion equation
    1,987.78 : 2,741.23 = 1,278.90 : x
  2. Step 2: Convert to fraction form
    1,987.78/2,741.23 = 1,278.90/x
  3. Step 3: Cross multiply
    1,987.78x = 2,741.23 × 1,278.90
  4. Step 4: Simplify right side
    1,987.78x = 3,505,759.05
  5. Step 5: Solve for x
    x = 3,505,759.05/1,987.78
  6. Step 6: Final answer
    x = 1,763.66

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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.