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Finding the Fourth Proportional to 831.65, 1,247.36 and 485.15

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Solution

The fourth proportional to 831.65, 1,247.36 and 485.15 is: 727.65

Step by Step Solution

  1. Step 1: Write the proportion equation
    831.65 : 1,247.36 = 485.15 : x
  2. Step 2: Convert to fraction form
    831.65/1,247.36 = 485.15/x
  3. Step 3: Cross multiply
    831.65x = 1,247.36 × 485.15
  4. Step 4: Simplify right side
    831.65x = 605,148.95
  5. Step 5: Solve for x
    x = 605,148.95/831.65
  6. Step 6: Final answer
    x = 727.65

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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.