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Finding the Fourth Proportional to 643.80, 886.48 and 486.68

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Solution

The fourth proportional to 643.80, 886.48 and 486.68 is: 670.13

Step by Step Solution

  1. Step 1: Write the proportion equation
    643.80 : 886.48 = 486.68 : x
  2. Step 2: Convert to fraction form
    643.80/886.48 = 486.68/x
  3. Step 3: Cross multiply
    643.80x = 886.48 × 486.68
  4. Step 4: Simplify right side
    643.80x = 431,432.09
  5. Step 5: Solve for x
    x = 431,432.09/643.80
  6. Step 6: Final answer
    x = 670.13

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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.