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Finding the Fourth Proportional to 987.49, 1,361.47 and 809.80

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Solution

The fourth proportional to 987.49, 1,361.47 and 809.80 is: 1,116.49

Step by Step Solution

  1. Step 1: Write the proportion equation
    987.49 : 1,361.47 = 809.80 : x
  2. Step 2: Convert to fraction form
    987.49/1,361.47 = 809.80/x
  3. Step 3: Cross multiply
    987.49x = 1,361.47 × 809.80
  4. Step 4: Simplify right side
    987.49x = 1,102,518.41
  5. Step 5: Solve for x
    x = 1,102,518.41/987.49
  6. Step 6: Final answer
    x = 1,116.49

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Why These Related Problems?

These problems maintain the same ratio (1.38) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.