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Finding the Fourth Proportional to 704.80, 1,057.20 and 690.40

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Solution

The fourth proportional to 704.80, 1,057.20 and 690.40 is: 1,035.60

Step by Step Solution

  1. Step 1: Write the proportion equation
    704.80 : 1,057.20 = 690.40 : x
  2. Step 2: Convert to fraction form
    704.80/1,057.20 = 690.40/x
  3. Step 3: Cross multiply
    704.80x = 1,057.20 × 690.40
  4. Step 4: Simplify right side
    704.80x = 729,890.88
  5. Step 5: Solve for x
    x = 729,890.88/704.80
  6. Step 6: Final answer
    x = 1,035.60

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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.