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Finding the Fourth Proportional to 1,290.72, 1,782 and 897.60

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Solution

The fourth proportional to 1,290.72, 1,782 and 897.60 is: 1,239.25

Step by Step Solution

  1. Step 1: Write the proportion equation
    1,290.72 : 1,782 = 897.60 : x
  2. Step 2: Convert to fraction form
    1,290.72/1,782 = 897.60/x
  3. Step 3: Cross multiply
    1,290.72x = 1,782 × 897.60
  4. Step 4: Simplify right side
    1,290.72x = 1,599,523.20
  5. Step 5: Solve for x
    x = 1,599,523.20/1,290.72
  6. Step 6: Final answer
    x = 1,239.25

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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.