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Finding the Fourth Proportional to 980.79, 1,352.91 and 669.75

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Solution

The fourth proportional to 980.79, 1,352.91 and 669.75 is: 923.86

Step by Step Solution

  1. Step 1: Write the proportion equation
    980.79 : 1,352.91 = 669.75 : x
  2. Step 2: Convert to fraction form
    980.79/1,352.91 = 669.75/x
  3. Step 3: Cross multiply
    980.79x = 1,352.91 × 669.75
  4. Step 4: Simplify right side
    980.79x = 906,111.47
  5. Step 5: Solve for x
    x = 906,111.47/980.79
  6. Step 6: Final answer
    x = 923.86

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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.