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Finding the Fourth Proportional to 643.48, 965.70 and 515.80

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Solution

The fourth proportional to 643.48, 965.70 and 515.80 is: 774.08

Step by Step Solution

  1. Step 1: Write the proportion equation
    643.48 : 965.70 = 515.80 : x
  2. Step 2: Convert to fraction form
    643.48/965.70 = 515.80/x
  3. Step 3: Cross multiply
    643.48x = 965.70 × 515.80
  4. Step 4: Simplify right side
    643.48x = 498,108.06
  5. Step 5: Solve for x
    x = 498,108.06/643.48
  6. Step 6: Final answer
    x = 774.08

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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.