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Finding the Fourth Proportional to 903.79, 1,247.21 and 489.79

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Solution

The fourth proportional to 903.79, 1,247.21 and 489.79 is: 675.90

Step by Step Solution

  1. Step 1: Write the proportion equation
    903.79 : 1,247.21 = 489.79 : x
  2. Step 2: Convert to fraction form
    903.79/1,247.21 = 489.79/x
  3. Step 3: Cross multiply
    903.79x = 1,247.21 × 489.79
  4. Step 4: Simplify right side
    903.79x = 610,870.99
  5. Step 5: Solve for x
    x = 610,870.99/903.79
  6. Step 6: Final answer
    x = 675.90

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Why These Related Problems?

These problems maintain the same ratio (1.38) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.