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Finding the Fourth Proportional to 643.52, 964.20 and 515

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Solution

The fourth proportional to 643.52, 964.20 and 515 is: 771.64

Step by Step Solution

  1. Step 1: Write the proportion equation
    643.52 : 964.20 = 515 : x
  2. Step 2: Convert to fraction form
    643.52/964.20 = 515/x
  3. Step 3: Cross multiply
    643.52x = 964.20 × 515
  4. Step 4: Simplify right side
    643.52x = 496,563
  5. Step 5: Solve for x
    x = 496,563/643.52
  6. Step 6: Final answer
    x = 771.64

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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.