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Finding the Fourth Proportional to 661.21, 989.74 and 515.37

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Solution

The fourth proportional to 661.21, 989.74 and 515.37 is: 771.44

Step by Step Solution

  1. Step 1: Write the proportion equation
    661.21 : 989.74 = 515.37 : x
  2. Step 2: Convert to fraction form
    661.21/989.74 = 515.37/x
  3. Step 3: Cross multiply
    661.21x = 989.74 × 515.37
  4. Step 4: Simplify right side
    661.21x = 510,082.30
  5. Step 5: Solve for x
    x = 510,082.30/661.21
  6. Step 6: Final answer
    x = 771.44

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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.