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Finding the Fourth Proportional to 1,387.25, 2,080.88 and 809.72

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Solution

The fourth proportional to 1,387.25, 2,080.88 and 809.72 is: 1,214.58

Step by Step Solution

  1. Step 1: Write the proportion equation
    1,387.25 : 2,080.88 = 809.72 : x
  2. Step 2: Convert to fraction form
    1,387.25/2,080.88 = 809.72/x
  3. Step 3: Cross multiply
    1,387.25x = 2,080.88 × 809.72
  4. Step 4: Simplify right side
    1,387.25x = 1,684,915.70
  5. Step 5: Solve for x
    x = 1,684,915.70/1,387.25
  6. Step 6: Final answer
    x = 1,214.58

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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.