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Finding the Fourth Proportional to 680.74, 1,020.20 and 290.39

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Solution

The fourth proportional to 680.74, 1,020.20 and 290.39 is: 435.19

Step by Step Solution

  1. Step 1: Write the proportion equation
    680.74 : 1,020.20 = 290.39 : x
  2. Step 2: Convert to fraction form
    680.74/1,020.20 = 290.39/x
  3. Step 3: Cross multiply
    680.74x = 1,020.20 × 290.39
  4. Step 4: Simplify right side
    680.74x = 296,249.33
  5. Step 5: Solve for x
    x = 296,249.33/680.74
  6. Step 6: Final answer
    x = 435.19

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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.