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Finding the Fourth Proportional to 699.80, 1,049.70 and 642.20

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Solution

The fourth proportional to 699.80, 1,049.70 and 642.20 is: 963.30

Step by Step Solution

  1. Step 1: Write the proportion equation
    699.80 : 1,049.70 = 642.20 : x
  2. Step 2: Convert to fraction form
    699.80/1,049.70 = 642.20/x
  3. Step 3: Cross multiply
    699.80x = 1,049.70 × 642.20
  4. Step 4: Simplify right side
    699.80x = 674,117.34
  5. Step 5: Solve for x
    x = 674,117.34/699.80
  6. Step 6: Final answer
    x = 963.30

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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.