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Finding the Fourth Proportional to 980.79, 1,353.46 and 561.30

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Solution

The fourth proportional to 980.79, 1,353.46 and 561.30 is: 774.58

Step by Step Solution

  1. Step 1: Write the proportion equation
    980.79 : 1,353.46 = 561.30 : x
  2. Step 2: Convert to fraction form
    980.79/1,353.46 = 561.30/x
  3. Step 3: Cross multiply
    980.79x = 1,353.46 × 561.30
  4. Step 4: Simplify right side
    980.79x = 759,697.10
  5. Step 5: Solve for x
    x = 759,697.10/980.79
  6. Step 6: Final answer
    x = 774.58

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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.