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Finding the Fourth Proportional to 680.81, 1,021.41 and 315.90

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Solution

The fourth proportional to 680.81, 1,021.41 and 315.90 is: 473.94

Step by Step Solution

  1. Step 1: Write the proportion equation
    680.81 : 1,021.41 = 315.90 : x
  2. Step 2: Convert to fraction form
    680.81/1,021.41 = 315.90/x
  3. Step 3: Cross multiply
    680.81x = 1,021.41 × 315.90
  4. Step 4: Simplify right side
    680.81x = 322,663.42
  5. Step 5: Solve for x
    x = 322,663.42/680.81
  6. Step 6: Final answer
    x = 473.94

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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.