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Finding the Fourth Proportional to 991.52, 1,485.80 and 748.21

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Solution

The fourth proportional to 991.52, 1,485.80 and 748.21 is: 1,121.20

Step by Step Solution

  1. Step 1: Write the proportion equation
    991.52 : 1,485.80 = 748.21 : x
  2. Step 2: Convert to fraction form
    991.52/1,485.80 = 748.21/x
  3. Step 3: Cross multiply
    991.52x = 1,485.80 × 748.21
  4. Step 4: Simplify right side
    991.52x = 1,111,690.42
  5. Step 5: Solve for x
    x = 1,111,690.42/991.52
  6. Step 6: Final answer
    x = 1,121.20

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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.