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Finding the Fourth Proportional to 1,285.71, 1,928.12 and 419.82

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Solution

The fourth proportional to 1,285.71, 1,928.12 and 419.82 is: 629.58

Step by Step Solution

  1. Step 1: Write the proportion equation
    1,285.71 : 1,928.12 = 419.82 : x
  2. Step 2: Convert to fraction form
    1,285.71/1,928.12 = 419.82/x
  3. Step 3: Cross multiply
    1,285.71x = 1,928.12 × 419.82
  4. Step 4: Simplify right side
    1,285.71x = 809,461.24
  5. Step 5: Solve for x
    x = 809,461.24/1,285.71
  6. Step 6: Final answer
    x = 629.58

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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.