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Finding the Fourth Proportional to 778.75, 1,173.49 and 644.80

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Solution

The fourth proportional to 778.75, 1,173.49 and 644.80 is: 971.64

Step by Step Solution

  1. Step 1: Write the proportion equation
    778.75 : 1,173.49 = 644.80 : x
  2. Step 2: Convert to fraction form
    778.75/1,173.49 = 644.80/x
  3. Step 3: Cross multiply
    778.75x = 1,173.49 × 644.80
  4. Step 4: Simplify right side
    778.75x = 756,666.35
  5. Step 5: Solve for x
    x = 756,666.35/778.75
  6. Step 6: Final answer
    x = 971.64

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Why These Related Problems?

These problems maintain the same ratio (1.51) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.