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Finding the Fourth Proportional to 659.68, 989.10 and 428.28

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Solution

The fourth proportional to 659.68, 989.10 and 428.28 is: 642.15

Step by Step Solution

  1. Step 1: Write the proportion equation
    659.68 : 989.10 = 428.28 : x
  2. Step 2: Convert to fraction form
    659.68/989.10 = 428.28/x
  3. Step 3: Cross multiply
    659.68x = 989.10 × 428.28
  4. Step 4: Simplify right side
    659.68x = 423,611.75
  5. Step 5: Solve for x
    x = 423,611.75/659.68
  6. Step 6: Final answer
    x = 642.15

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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.