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Finding the Fourth Proportional to 661.98, 992.82 and 390

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Solution

The fourth proportional to 661.98, 992.82 and 390 is: 584.91

Step by Step Solution

  1. Step 1: Write the proportion equation
    661.98 : 992.82 = 390 : x
  2. Step 2: Convert to fraction form
    661.98/992.82 = 390/x
  3. Step 3: Cross multiply
    661.98x = 992.82 × 390
  4. Step 4: Simplify right side
    661.98x = 387,199.80
  5. Step 5: Solve for x
    x = 387,199.80/661.98
  6. Step 6: Final answer
    x = 584.91

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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.