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Finding the Fourth Proportional to 687.96, 1,028.90 and 615.42

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Solution

The fourth proportional to 687.96, 1,028.90 and 615.42 is: 920.41

Step by Step Solution

  1. Step 1: Write the proportion equation
    687.96 : 1,028.90 = 615.42 : x
  2. Step 2: Convert to fraction form
    687.96/1,028.90 = 615.42/x
  3. Step 3: Cross multiply
    687.96x = 1,028.90 × 615.42
  4. Step 4: Simplify right side
    687.96x = 633,205.64
  5. Step 5: Solve for x
    x = 633,205.64/687.96
  6. Step 6: Final answer
    x = 920.41

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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.