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Finding the Fourth Proportional to 991.58, 1,485.68 and 644.38

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Solution

The fourth proportional to 991.58, 1,485.68 and 644.38 is: 965.47

Step by Step Solution

  1. Step 1: Write the proportion equation
    991.58 : 1,485.68 = 644.38 : x
  2. Step 2: Convert to fraction form
    991.58/1,485.68 = 644.38/x
  3. Step 3: Cross multiply
    991.58x = 1,485.68 × 644.38
  4. Step 4: Simplify right side
    991.58x = 957,335.54
  5. Step 5: Solve for x
    x = 957,335.54/991.58
  6. Step 6: Final answer
    x = 965.47

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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.