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Finding the Fourth Proportional to 921.72, 1,381.64 and 435.20

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Solution

The fourth proportional to 921.72, 1,381.64 and 435.20 is: 652.36

Step by Step Solution

  1. Step 1: Write the proportion equation
    921.72 : 1,381.64 = 435.20 : x
  2. Step 2: Convert to fraction form
    921.72/1,381.64 = 435.20/x
  3. Step 3: Cross multiply
    921.72x = 1,381.64 × 435.20
  4. Step 4: Simplify right side
    921.72x = 601,289.73
  5. Step 5: Solve for x
    x = 601,289.73/921.72
  6. Step 6: Final answer
    x = 652.36

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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.