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Finding the Fourth Proportional to 775.63, 1,161.38 and 639.28

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Solution

The fourth proportional to 775.63, 1,161.38 and 639.28 is: 957.22

Step by Step Solution

  1. Step 1: Write the proportion equation
    775.63 : 1,161.38 = 639.28 : x
  2. Step 2: Convert to fraction form
    775.63/1,161.38 = 639.28/x
  3. Step 3: Cross multiply
    775.63x = 1,161.38 × 639.28
  4. Step 4: Simplify right side
    775.63x = 742,447.01
  5. Step 5: Solve for x
    x = 742,447.01/775.63
  6. Step 6: Final answer
    x = 957.22

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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.