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Finding the Fourth Proportional to 680.77, 1,021.20 and 315.46

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Solution

The fourth proportional to 680.77, 1,021.20 and 315.46 is: 473.21

Step by Step Solution

  1. Step 1: Write the proportion equation
    680.77 : 1,021.20 = 315.46 : x
  2. Step 2: Convert to fraction form
    680.77/1,021.20 = 315.46/x
  3. Step 3: Cross multiply
    680.77x = 1,021.20 × 315.46
  4. Step 4: Simplify right side
    680.77x = 322,147.75
  5. Step 5: Solve for x
    x = 322,147.75/680.77
  6. Step 6: Final answer
    x = 473.21

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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.