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Finding the Fourth Proportional to 980.72, 1,353.74 and 686.85

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Solution

The fourth proportional to 980.72, 1,353.74 and 686.85 is: 948.09

Step by Step Solution

  1. Step 1: Write the proportion equation
    980.72 : 1,353.74 = 686.85 : x
  2. Step 2: Convert to fraction form
    980.72/1,353.74 = 686.85/x
  3. Step 3: Cross multiply
    980.72x = 1,353.74 × 686.85
  4. Step 4: Simplify right side
    980.72x = 929,807.81
  5. Step 5: Solve for x
    x = 929,807.81/980.72
  6. Step 6: Final answer
    x = 948.09

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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.