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Finding the Fourth Proportional to 643.02, 963.60 and 399.40

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Solution

The fourth proportional to 643.02, 963.60 and 399.40 is: 598.53

Step by Step Solution

  1. Step 1: Write the proportion equation
    643.02 : 963.60 = 399.40 : x
  2. Step 2: Convert to fraction form
    643.02/963.60 = 399.40/x
  3. Step 3: Cross multiply
    643.02x = 963.60 × 399.40
  4. Step 4: Simplify right side
    643.02x = 384,861.84
  5. Step 5: Solve for x
    x = 384,861.84/643.02
  6. Step 6: Final answer
    x = 598.53

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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.