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Finding the Fourth Proportional to 643.80, 888.66 and 419.76

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Solution

The fourth proportional to 643.80, 888.66 and 419.76 is: 579.41

Step by Step Solution

  1. Step 1: Write the proportion equation
    643.80 : 888.66 = 419.76 : x
  2. Step 2: Convert to fraction form
    643.80/888.66 = 419.76/x
  3. Step 3: Cross multiply
    643.80x = 888.66 × 419.76
  4. Step 4: Simplify right side
    643.80x = 373,023.92
  5. Step 5: Solve for x
    x = 373,023.92/643.80
  6. Step 6: Final answer
    x = 579.41

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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.