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Finding the Fourth Proportional to 991.22, 1,485.18 and 644.12

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Solution

The fourth proportional to 991.22, 1,485.18 and 644.12 is: 965.11

Step by Step Solution

  1. Step 1: Write the proportion equation
    991.22 : 1,485.18 = 644.12 : x
  2. Step 2: Convert to fraction form
    991.22/1,485.18 = 644.12/x
  3. Step 3: Cross multiply
    991.22x = 1,485.18 × 644.12
  4. Step 4: Simplify right side
    991.22x = 956,634.14
  5. Step 5: Solve for x
    x = 956,634.14/991.22
  6. Step 6: Final answer
    x = 965.11

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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.