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Finding the Fourth Proportional to 670.24, 1,005.72 and 639.28

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Solution

The fourth proportional to 670.24, 1,005.72 and 639.28 is: 959.26

Step by Step Solution

  1. Step 1: Write the proportion equation
    670.24 : 1,005.72 = 639.28 : x
  2. Step 2: Convert to fraction form
    670.24/1,005.72 = 639.28/x
  3. Step 3: Cross multiply
    670.24x = 1,005.72 × 639.28
  4. Step 4: Simplify right side
    670.24x = 642,936.68
  5. Step 5: Solve for x
    x = 642,936.68/670.24
  6. Step 6: Final answer
    x = 959.26

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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.