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Finding the Fourth Proportional to 1,861, 2,568.80 and 1,115.20

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Solution

The fourth proportional to 1,861, 2,568.80 and 1,115.20 is: 1,539.35

Step by Step Solution

  1. Step 1: Write the proportion equation
    1,861 : 2,568.80 = 1,115.20 : x
  2. Step 2: Convert to fraction form
    1,861/2,568.80 = 1,115.20/x
  3. Step 3: Cross multiply
    1,861x = 2,568.80 × 1,115.20
  4. Step 4: Simplify right side
    1,861x = 2,864,725.76
  5. Step 5: Solve for x
    x = 2,864,725.76/1,861
  6. Step 6: Final answer
    x = 1,539.35

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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.