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Finding the Fourth Proportional to 1,387.68, 2,080.56 and 618.72

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Solution

The fourth proportional to 1,387.68, 2,080.56 and 618.72 is: 927.65

Step by Step Solution

  1. Step 1: Write the proportion equation
    1,387.68 : 2,080.56 = 618.72 : x
  2. Step 2: Convert to fraction form
    1,387.68/2,080.56 = 618.72/x
  3. Step 3: Cross multiply
    1,387.68x = 2,080.56 × 618.72
  4. Step 4: Simplify right side
    1,387.68x = 1,287,284.08
  5. Step 5: Solve for x
    x = 1,287,284.08/1,387.68
  6. Step 6: Final answer
    x = 927.65

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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.