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Finding the Fourth Proportional to 659.94, 987.93 and 428.16

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Solution

The fourth proportional to 659.94, 987.93 and 428.16 is: 640.96

Step by Step Solution

  1. Step 1: Write the proportion equation
    659.94 : 987.93 = 428.16 : x
  2. Step 2: Convert to fraction form
    659.94/987.93 = 428.16/x
  3. Step 3: Cross multiply
    659.94x = 987.93 × 428.16
  4. Step 4: Simplify right side
    659.94x = 422,992.11
  5. Step 5: Solve for x
    x = 422,992.11/659.94
  6. Step 6: Final answer
    x = 640.96

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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.