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Finding the Fourth Proportional to 1,386.12, 2,077.56 and 615

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Solution

The fourth proportional to 1,386.12, 2,077.56 and 615 is: 921.78

Step by Step Solution

  1. Step 1: Write the proportion equation
    1,386.12 : 2,077.56 = 615 : x
  2. Step 2: Convert to fraction form
    1,386.12/2,077.56 = 615/x
  3. Step 3: Cross multiply
    1,386.12x = 2,077.56 × 615
  4. Step 4: Simplify right side
    1,386.12x = 1,277,699.40
  5. Step 5: Solve for x
    x = 1,277,699.40/1,386.12
  6. Step 6: Final answer
    x = 921.78

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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.