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Finding the Fourth Proportional to 1,108.80, 1,661.40 and 817.20

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Solution

The fourth proportional to 1,108.80, 1,661.40 and 817.20 is: 1,224.47

Step by Step Solution

  1. Step 1: Write the proportion equation
    1,108.80 : 1,661.40 = 817.20 : x
  2. Step 2: Convert to fraction form
    1,108.80/1,661.40 = 817.20/x
  3. Step 3: Cross multiply
    1,108.80x = 1,661.40 × 817.20
  4. Step 4: Simplify right side
    1,108.80x = 1,357,696.08
  5. Step 5: Solve for x
    x = 1,357,696.08/1,108.80
  6. Step 6: Final answer
    x = 1,224.47

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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.