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Finding the Fourth Proportional to 689.28, 1,034.16 and 256.72

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Solution

The fourth proportional to 689.28, 1,034.16 and 256.72 is: 385.17

Step by Step Solution

  1. Step 1: Write the proportion equation
    689.28 : 1,034.16 = 256.72 : x
  2. Step 2: Convert to fraction form
    689.28/1,034.16 = 256.72/x
  3. Step 3: Cross multiply
    689.28x = 1,034.16 × 256.72
  4. Step 4: Simplify right side
    689.28x = 265,489.56
  5. Step 5: Solve for x
    x = 265,489.56/689.28
  6. Step 6: Final answer
    x = 385.17

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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.