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Finding the Fourth Proportional to 696.70, 1,045.05 and 643.90

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Solution

The fourth proportional to 696.70, 1,045.05 and 643.90 is: 965.85

Step by Step Solution

  1. Step 1: Write the proportion equation
    696.70 : 1,045.05 = 643.90 : x
  2. Step 2: Convert to fraction form
    696.70/1,045.05 = 643.90/x
  3. Step 3: Cross multiply
    696.70x = 1,045.05 × 643.90
  4. Step 4: Simplify right side
    696.70x = 672,907.70
  5. Step 5: Solve for x
    x = 672,907.70/696.70
  6. Step 6: Final answer
    x = 965.85

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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.