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Finding the Fourth Proportional to 615, 921.60 and 512.40

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Solution

The fourth proportional to 615, 921.60 and 512.40 is: 767.85

Step by Step Solution

  1. Step 1: Write the proportion equation
    615 : 921.60 = 512.40 : x
  2. Step 2: Convert to fraction form
    615/921.60 = 512.40/x
  3. Step 3: Cross multiply
    615x = 921.60 × 512.40
  4. Step 4: Simplify right side
    615x = 472,227.84
  5. Step 5: Solve for x
    x = 472,227.84/615
  6. Step 6: Final answer
    x = 767.85

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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.