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Finding the Fourth Proportional to 904.50, 1,355.20 and 643.21

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Solution

The fourth proportional to 904.50, 1,355.20 and 643.21 is: 963.71

Step by Step Solution

  1. Step 1: Write the proportion equation
    904.50 : 1,355.20 = 643.21 : x
  2. Step 2: Convert to fraction form
    904.50/1,355.20 = 643.21/x
  3. Step 3: Cross multiply
    904.50x = 1,355.20 × 643.21
  4. Step 4: Simplify right side
    904.50x = 871,673.20
  5. Step 5: Solve for x
    x = 871,673.20/904.50
  6. Step 6: Final answer
    x = 963.71

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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.