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Finding the Fourth Proportional to 661.16, 991.79 and 387.29

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Solution

The fourth proportional to 661.16, 991.79 and 387.29 is: 580.96

Step by Step Solution

  1. Step 1: Write the proportion equation
    661.16 : 991.79 = 387.29 : x
  2. Step 2: Convert to fraction form
    661.16/991.79 = 387.29/x
  3. Step 3: Cross multiply
    661.16x = 991.79 × 387.29
  4. Step 4: Simplify right side
    661.16x = 384,110.35
  5. Step 5: Solve for x
    x = 384,110.35/661.16
  6. Step 6: Final answer
    x = 580.96

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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.