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Finding the Fourth Proportional to 680.85, 1,020.06 and 644.40

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Solution

The fourth proportional to 680.85, 1,020.06 and 644.40 is: 965.45

Step by Step Solution

  1. Step 1: Write the proportion equation
    680.85 : 1,020.06 = 644.40 : x
  2. Step 2: Convert to fraction form
    680.85/1,020.06 = 644.40/x
  3. Step 3: Cross multiply
    680.85x = 1,020.06 × 644.40
  4. Step 4: Simplify right side
    680.85x = 657,326.66
  5. Step 5: Solve for x
    x = 657,326.66/680.85
  6. Step 6: Final answer
    x = 965.45

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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.