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Finding the Fourth Proportional to 680.66, 1,020.64 and 407.28

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Solution

The fourth proportional to 680.66, 1,020.64 and 407.28 is: 610.71

Step by Step Solution

  1. Step 1: Write the proportion equation
    680.66 : 1,020.64 = 407.28 : x
  2. Step 2: Convert to fraction form
    680.66/1,020.64 = 407.28/x
  3. Step 3: Cross multiply
    680.66x = 1,020.64 × 407.28
  4. Step 4: Simplify right side
    680.66x = 415,686.26
  5. Step 5: Solve for x
    x = 415,686.26/680.66
  6. Step 6: Final answer
    x = 610.71

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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.