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Finding the Fourth Proportional to 921.66, 1,382.80 and 644.30

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Solution

The fourth proportional to 921.66, 1,382.80 and 644.30 is: 966.67

Step by Step Solution

  1. Step 1: Write the proportion equation
    921.66 : 1,382.80 = 644.30 : x
  2. Step 2: Convert to fraction form
    921.66/1,382.80 = 644.30/x
  3. Step 3: Cross multiply
    921.66x = 1,382.80 × 644.30
  4. Step 4: Simplify right side
    921.66x = 890,938.04
  5. Step 5: Solve for x
    x = 890,938.04/921.66
  6. Step 6: Final answer
    x = 966.67

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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.