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Finding the Fourth Proportional to 661, 911.40 and 427.72

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Solution

The fourth proportional to 661, 911.40 and 427.72 is: 589.75

Step by Step Solution

  1. Step 1: Write the proportion equation
    661 : 911.40 = 427.72 : x
  2. Step 2: Convert to fraction form
    661/911.40 = 427.72/x
  3. Step 3: Cross multiply
    661x = 911.40 × 427.72
  4. Step 4: Simplify right side
    661x = 389,824.01
  5. Step 5: Solve for x
    x = 389,824.01/661
  6. Step 6: Final answer
    x = 589.75

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Why These Related Problems?

These problems maintain the same ratio (1.38) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.