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Finding the Fourth Proportional to 991.32, 1,489.14 and 809.16

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Solution

The fourth proportional to 991.32, 1,489.14 and 809.16 is: 1,215.50

Step by Step Solution

  1. Step 1: Write the proportion equation
    991.32 : 1,489.14 = 809.16 : x
  2. Step 2: Convert to fraction form
    991.32/1,489.14 = 809.16/x
  3. Step 3: Cross multiply
    991.32x = 1,489.14 × 809.16
  4. Step 4: Simplify right side
    991.32x = 1,204,952.52
  5. Step 5: Solve for x
    x = 1,204,952.52/991.32
  6. Step 6: Final answer
    x = 1,215.50

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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.