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Finding the Fourth Proportional to 686, 1,028.90 and 253.08

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Solution

The fourth proportional to 686, 1,028.90 and 253.08 is: 379.58

Step by Step Solution

  1. Step 1: Write the proportion equation
    686 : 1,028.90 = 253.08 : x
  2. Step 2: Convert to fraction form
    686/1,028.90 = 253.08/x
  3. Step 3: Cross multiply
    686x = 1,028.90 × 253.08
  4. Step 4: Simplify right side
    686x = 260,394.01
  5. Step 5: Solve for x
    x = 260,394.01/686
  6. Step 6: Final answer
    x = 379.58

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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.