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Finding the Fourth Proportional to 991.12, 1,487.22 and 988

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Solution

The fourth proportional to 991.12, 1,487.22 and 988 is: 1,482.54

Step by Step Solution

  1. Step 1: Write the proportion equation
    991.12 : 1,487.22 = 988 : x
  2. Step 2: Convert to fraction form
    991.12/1,487.22 = 988/x
  3. Step 3: Cross multiply
    991.12x = 1,487.22 × 988
  4. Step 4: Simplify right side
    991.12x = 1,469,373.36
  5. Step 5: Solve for x
    x = 1,469,373.36/991.12
  6. Step 6: Final answer
    x = 1,482.54

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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.