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Finding the Fourth Proportional to 661.06, 991.29 and 387.23

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Solution

The fourth proportional to 661.06, 991.29 and 387.23 is: 580.67

Step by Step Solution

  1. Step 1: Write the proportion equation
    661.06 : 991.29 = 387.23 : x
  2. Step 2: Convert to fraction form
    661.06/991.29 = 387.23/x
  3. Step 3: Cross multiply
    661.06x = 991.29 × 387.23
  4. Step 4: Simplify right side
    661.06x = 383,857.12
  5. Step 5: Solve for x
    x = 383,857.12/661.06
  6. Step 6: Final answer
    x = 580.67

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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.