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Finding the Fourth Proportional to 1,286.04, 1,929.09 and 420.42

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Solution

The fourth proportional to 1,286.04, 1,929.09 and 420.42 is: 630.64

Step by Step Solution

  1. Step 1: Write the proportion equation
    1,286.04 : 1,929.09 = 420.42 : x
  2. Step 2: Convert to fraction form
    1,286.04/1,929.09 = 420.42/x
  3. Step 3: Cross multiply
    1,286.04x = 1,929.09 × 420.42
  4. Step 4: Simplify right side
    1,286.04x = 811,028.02
  5. Step 5: Solve for x
    x = 811,028.02/1,286.04
  6. Step 6: Final answer
    x = 630.64

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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.