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Finding the Fourth Proportional to 643.80, 965.69 and 318.93

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Solution

The fourth proportional to 643.80, 965.69 and 318.93 is: 478.39

Step by Step Solution

  1. Step 1: Write the proportion equation
    643.80 : 965.69 = 318.93 : x
  2. Step 2: Convert to fraction form
    643.80/965.69 = 318.93/x
  3. Step 3: Cross multiply
    643.80x = 965.69 × 318.93
  4. Step 4: Simplify right side
    643.80x = 307,987.51
  5. Step 5: Solve for x
    x = 307,987.51/643.80
  6. Step 6: Final answer
    x = 478.39

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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.