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Finding the Fourth Proportional to 643.40, 887.64 and 447.40

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Solution

The fourth proportional to 643.40, 887.64 and 447.40 is: 617.24

Step by Step Solution

  1. Step 1: Write the proportion equation
    643.40 : 887.64 = 447.40 : x
  2. Step 2: Convert to fraction form
    643.40/887.64 = 447.40/x
  3. Step 3: Cross multiply
    643.40x = 887.64 × 447.40
  4. Step 4: Simplify right side
    643.40x = 397,130.14
  5. Step 5: Solve for x
    x = 397,130.14/643.40
  6. Step 6: Final answer
    x = 617.24

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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.