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Finding the Fourth Proportional to 991.20, 1,486.80 and 297.80

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Solution

The fourth proportional to 991.20, 1,486.80 and 297.80 is: 446.70

Step by Step Solution

  1. Step 1: Write the proportion equation
    991.20 : 1,486.80 = 297.80 : x
  2. Step 2: Convert to fraction form
    991.20/1,486.80 = 297.80/x
  3. Step 3: Cross multiply
    991.20x = 1,486.80 × 297.80
  4. Step 4: Simplify right side
    991.20x = 442,772.76
  5. Step 5: Solve for x
    x = 442,772.76/991.20
  6. Step 6: Final answer
    x = 446.70

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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.