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Finding the Fourth Proportional to 830.96, 1,247.20 and 420.38

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Solution

The fourth proportional to 830.96, 1,247.20 and 420.38 is: 630.95

Step by Step Solution

  1. Step 1: Write the proportion equation
    830.96 : 1,247.20 = 420.38 : x
  2. Step 2: Convert to fraction form
    830.96/1,247.20 = 420.38/x
  3. Step 3: Cross multiply
    830.96x = 1,247.20 × 420.38
  4. Step 4: Simplify right side
    830.96x = 524,297.94
  5. Step 5: Solve for x
    x = 524,297.94/830.96
  6. Step 6: Final answer
    x = 630.95

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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.