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Finding the Fourth Proportional to 680.81, 1,021.28 and 315.70

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Solution

The fourth proportional to 680.81, 1,021.28 and 315.70 is: 473.59

Step by Step Solution

  1. Step 1: Write the proportion equation
    680.81 : 1,021.28 = 315.70 : x
  2. Step 2: Convert to fraction form
    680.81/1,021.28 = 315.70/x
  3. Step 3: Cross multiply
    680.81x = 1,021.28 × 315.70
  4. Step 4: Simplify right side
    680.81x = 322,421.44
  5. Step 5: Solve for x
    x = 322,421.44/680.81
  6. Step 6: Final answer
    x = 473.59

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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.