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Finding the Fourth Proportional to 1,387.07, 2,080.00 and 520.78

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Solution

The fourth proportional to 1,387.07, 2,080.00 and 520.78 is: 780.93

Step by Step Solution

  1. Step 1: Write the proportion equation
    1,387.07 : 2,080.00 = 520.78 : x
  2. Step 2: Convert to fraction form
    1,387.07/2,080.00 = 520.78/x
  3. Step 3: Cross multiply
    1,387.07x = 2,080.00 × 520.78
  4. Step 4: Simplify right side
    1,387.07x = 1,083,209.40
  5. Step 5: Solve for x
    x = 1,083,209.40/1,387.07
  6. Step 6: Final answer
    x = 780.93

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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.