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Finding the Fourth Proportional to 831.51, 1,247.17 and 420.44

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Solution

The fourth proportional to 831.51, 1,247.17 and 420.44 is: 630.61

Step by Step Solution

  1. Step 1: Write the proportion equation
    831.51 : 1,247.17 = 420.44 : x
  2. Step 2: Convert to fraction form
    831.51/1,247.17 = 420.44/x
  3. Step 3: Cross multiply
    831.51x = 1,247.17 × 420.44
  4. Step 4: Simplify right side
    831.51x = 524,355.99
  5. Step 5: Solve for x
    x = 524,355.99/831.51
  6. Step 6: Final answer
    x = 630.61

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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.