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Finding the Fourth Proportional to 1,387.11, 2,080.79 and 521.49

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Solution

The fourth proportional to 1,387.11, 2,080.79 and 521.49 is: 782.28

Step by Step Solution

  1. Step 1: Write the proportion equation
    1,387.11 : 2,080.79 = 521.49 : x
  2. Step 2: Convert to fraction form
    1,387.11/2,080.79 = 521.49/x
  3. Step 3: Cross multiply
    1,387.11x = 2,080.79 × 521.49
  4. Step 4: Simplify right side
    1,387.11x = 1,085,108.57
  5. Step 5: Solve for x
    x = 1,085,108.57/1,387.11
  6. Step 6: Final answer
    x = 782.28

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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.