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Finding the Fourth Proportional to 980.91, 1,353.90 and 561.39

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Solution

The fourth proportional to 980.91, 1,353.90 and 561.39 is: 774.86

Step by Step Solution

  1. Step 1: Write the proportion equation
    980.91 : 1,353.90 = 561.39 : x
  2. Step 2: Convert to fraction form
    980.91/1,353.90 = 561.39/x
  3. Step 3: Cross multiply
    980.91x = 1,353.90 × 561.39
  4. Step 4: Simplify right side
    980.91x = 760,063.60
  5. Step 5: Solve for x
    x = 760,063.60/980.91
  6. Step 6: Final answer
    x = 774.86

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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.