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Finding the Fourth Proportional to 680.76, 1,020.78 and 437.40

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Solution

The fourth proportional to 680.76, 1,020.78 and 437.40 is: 655.87

Step by Step Solution

  1. Step 1: Write the proportion equation
    680.76 : 1,020.78 = 437.40 : x
  2. Step 2: Convert to fraction form
    680.76/1,020.78 = 437.40/x
  3. Step 3: Cross multiply
    680.76x = 1,020.78 × 437.40
  4. Step 4: Simplify right side
    680.76x = 446,489.17
  5. Step 5: Solve for x
    x = 446,489.17/680.76
  6. Step 6: Final answer
    x = 655.87

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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.