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Finding the Fourth Proportional to 1,285.65, 1,928.79 and 636.21

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Solution

The fourth proportional to 1,285.65, 1,928.79 and 636.21 is: 954.47

Step by Step Solution

  1. Step 1: Write the proportion equation
    1,285.65 : 1,928.79 = 636.21 : x
  2. Step 2: Convert to fraction form
    1,285.65/1,928.79 = 636.21/x
  3. Step 3: Cross multiply
    1,285.65x = 1,928.79 × 636.21
  4. Step 4: Simplify right side
    1,285.65x = 1,227,115.49
  5. Step 5: Solve for x
    x = 1,227,115.49/1,285.65
  6. Step 6: Final answer
    x = 954.47

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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.