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Finding the Fourth Proportional to 879.80, 1,320.90 and 697.40

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Solution

The fourth proportional to 879.80, 1,320.90 and 697.40 is: 1,047.05

Step by Step Solution

  1. Step 1: Write the proportion equation
    879.80 : 1,320.90 = 697.40 : x
  2. Step 2: Convert to fraction form
    879.80/1,320.90 = 697.40/x
  3. Step 3: Cross multiply
    879.80x = 1,320.90 × 697.40
  4. Step 4: Simplify right side
    879.80x = 921,195.66
  5. Step 5: Solve for x
    x = 921,195.66/879.80
  6. Step 6: Final answer
    x = 1,047.05

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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.