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Finding the Fourth Proportional to 768.79, 1,060.90 and 644.15

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Solution

The fourth proportional to 768.79, 1,060.90 and 644.15 is: 888.90

Step by Step Solution

  1. Step 1: Write the proportion equation
    768.79 : 1,060.90 = 644.15 : x
  2. Step 2: Convert to fraction form
    768.79/1,060.90 = 644.15/x
  3. Step 3: Cross multiply
    768.79x = 1,060.90 × 644.15
  4. Step 4: Simplify right side
    768.79x = 683,379.78
  5. Step 5: Solve for x
    x = 683,379.78/768.79
  6. Step 6: Final answer
    x = 888.90

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Why These Related Problems?

These problems maintain the same ratio (1.38) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.