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Finding the Fourth Proportional to 643.42, 886.99 and 421.99

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Solution

The fourth proportional to 643.42, 886.99 and 421.99 is: 581.73

Step by Step Solution

  1. Step 1: Write the proportion equation
    643.42 : 886.99 = 421.99 : x
  2. Step 2: Convert to fraction form
    643.42/886.99 = 421.99/x
  3. Step 3: Cross multiply
    643.42x = 886.99 × 421.99
  4. Step 4: Simplify right side
    643.42x = 374,294.37
  5. Step 5: Solve for x
    x = 374,294.37/643.42
  6. Step 6: Final answer
    x = 581.73

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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.