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Finding the Fourth Proportional to 1,120.40, 1,680.60 and 864.40

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Solution

The fourth proportional to 1,120.40, 1,680.60 and 864.40 is: 1,296.60

Step by Step Solution

  1. Step 1: Write the proportion equation
    1,120.40 : 1,680.60 = 864.40 : x
  2. Step 2: Convert to fraction form
    1,120.40/1,680.60 = 864.40/x
  3. Step 3: Cross multiply
    1,120.40x = 1,680.60 × 864.40
  4. Step 4: Simplify right side
    1,120.40x = 1,452,710.64
  5. Step 5: Solve for x
    x = 1,452,710.64/1,120.40
  6. Step 6: Final answer
    x = 1,296.60

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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.