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Finding the Fourth Proportional to 687.64, 1,031.40 and 254.75

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Solution

The fourth proportional to 687.64, 1,031.40 and 254.75 is: 382.10

Step by Step Solution

  1. Step 1: Write the proportion equation
    687.64 : 1,031.40 = 254.75 : x
  2. Step 2: Convert to fraction form
    687.64/1,031.40 = 254.75/x
  3. Step 3: Cross multiply
    687.64x = 1,031.40 × 254.75
  4. Step 4: Simplify right side
    687.64x = 262,749.15
  5. Step 5: Solve for x
    x = 262,749.15/687.64
  6. Step 6: Final answer
    x = 382.10

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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.