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Finding the Fourth Proportional to 1,118.90, 1,678.35 and 809.30

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Solution

The fourth proportional to 1,118.90, 1,678.35 and 809.30 is: 1,213.95

Step by Step Solution

  1. Step 1: Write the proportion equation
    1,118.90 : 1,678.35 = 809.30 : x
  2. Step 2: Convert to fraction form
    1,118.90/1,678.35 = 809.30/x
  3. Step 3: Cross multiply
    1,118.90x = 1,678.35 × 809.30
  4. Step 4: Simplify right side
    1,118.90x = 1,358,288.66
  5. Step 5: Solve for x
    x = 1,358,288.66/1,118.90
  6. Step 6: Final answer
    x = 1,213.95

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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.