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Finding the Fourth Proportional to 980.50, 1,352.68 and 644.28

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Solution

The fourth proportional to 980.50, 1,352.68 and 644.28 is: 888.84

Step by Step Solution

  1. Step 1: Write the proportion equation
    980.50 : 1,352.68 = 644.28 : x
  2. Step 2: Convert to fraction form
    980.50/1,352.68 = 644.28/x
  3. Step 3: Cross multiply
    980.50x = 1,352.68 × 644.28
  4. Step 4: Simplify right side
    980.50x = 871,504.67
  5. Step 5: Solve for x
    x = 871,504.67/980.50
  6. Step 6: Final answer
    x = 888.84

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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.