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Finding the Fourth Proportional to 685.24, 1,028.58 and 639.16

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Solution

The fourth proportional to 685.24, 1,028.58 and 639.16 is: 959.41

Step by Step Solution

  1. Step 1: Write the proportion equation
    685.24 : 1,028.58 = 639.16 : x
  2. Step 2: Convert to fraction form
    685.24/1,028.58 = 639.16/x
  3. Step 3: Cross multiply
    685.24x = 1,028.58 × 639.16
  4. Step 4: Simplify right side
    685.24x = 657,427.19
  5. Step 5: Solve for x
    x = 657,427.19/685.24
  6. Step 6: Final answer
    x = 959.41

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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.