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Finding the Fourth Proportional to 664.51, 991.74 and 647.23

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Solution

The fourth proportional to 664.51, 991.74 and 647.23 is: 965.95

Step by Step Solution

  1. Step 1: Write the proportion equation
    664.51 : 991.74 = 647.23 : x
  2. Step 2: Convert to fraction form
    664.51/991.74 = 647.23/x
  3. Step 3: Cross multiply
    664.51x = 991.74 × 647.23
  4. Step 4: Simplify right side
    664.51x = 641,883.88
  5. Step 5: Solve for x
    x = 641,883.88/664.51
  6. Step 6: Final answer
    x = 965.95

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Why These Related Problems?

These problems maintain the same ratio (1.49) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.