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Finding the Fourth Proportional to 831.24, 1,245.90 and 310.80

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Solution

The fourth proportional to 831.24, 1,245.90 and 310.80 is: 465.84

Step by Step Solution

  1. Step 1: Write the proportion equation
    831.24 : 1,245.90 = 310.80 : x
  2. Step 2: Convert to fraction form
    831.24/1,245.90 = 310.80/x
  3. Step 3: Cross multiply
    831.24x = 1,245.90 × 310.80
  4. Step 4: Simplify right side
    831.24x = 387,225.72
  5. Step 5: Solve for x
    x = 387,225.72/831.24
  6. Step 6: Final answer
    x = 465.84

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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.