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Finding the Fourth Proportional to 690.80, 1,035.60 and 343.92

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Solution

The fourth proportional to 690.80, 1,035.60 and 343.92 is: 515.58

Step by Step Solution

  1. Step 1: Write the proportion equation
    690.80 : 1,035.60 = 343.92 : x
  2. Step 2: Convert to fraction form
    690.80/1,035.60 = 343.92/x
  3. Step 3: Cross multiply
    690.80x = 1,035.60 × 343.92
  4. Step 4: Simplify right side
    690.80x = 356,163.55
  5. Step 5: Solve for x
    x = 356,163.55/690.80
  6. Step 6: Final answer
    x = 515.58

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Why These Related Problems?

These problems maintain the same ratio (1.50) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.