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Finding the Fourth Proportional to 680.58, 1,020.90 and 315.30

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Solution

The fourth proportional to 680.58, 1,020.90 and 315.30 is: 472.96

Step by Step Solution

  1. Step 1: Write the proportion equation
    680.58 : 1,020.90 = 315.30 : x
  2. Step 2: Convert to fraction form
    680.58/1,020.90 = 315.30/x
  3. Step 3: Cross multiply
    680.58x = 1,020.90 × 315.30
  4. Step 4: Simplify right side
    680.58x = 321,889.77
  5. Step 5: Solve for x
    x = 321,889.77/680.58
  6. Step 6: Final answer
    x = 472.96

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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.