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Finding the Fourth Proportional to 659.28, 989.16 and 428.04

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Solution

The fourth proportional to 659.28, 989.16 and 428.04 is: 642.22

Step by Step Solution

  1. Step 1: Write the proportion equation
    659.28 : 989.16 = 428.04 : x
  2. Step 2: Convert to fraction form
    659.28/989.16 = 428.04/x
  3. Step 3: Cross multiply
    659.28x = 989.16 × 428.04
  4. Step 4: Simplify right side
    659.28x = 423,400.05
  5. Step 5: Solve for x
    x = 423,400.05/659.28
  6. Step 6: Final answer
    x = 642.22

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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.