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Finding the Fourth Proportional to 1,386.78, 2,080.71 and 656.97

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Solution

The fourth proportional to 1,386.78, 2,080.71 and 656.97 is: 985.71

Step by Step Solution

  1. Step 1: Write the proportion equation
    1,386.78 : 2,080.71 = 656.97 : x
  2. Step 2: Convert to fraction form
    1,386.78/2,080.71 = 656.97/x
  3. Step 3: Cross multiply
    1,386.78x = 2,080.71 × 656.97
  4. Step 4: Simplify right side
    1,386.78x = 1,366,964.05
  5. Step 5: Solve for x
    x = 1,366,964.05/1,386.78
  6. Step 6: Final answer
    x = 985.71

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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.