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Finding the Fourth Proportional to 1,420.64, 2,128.61 and 871.66

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Solution

The fourth proportional to 1,420.64, 2,128.61 and 871.66 is: 1,306.05

Step by Step Solution

  1. Step 1: Write the proportion equation
    1,420.64 : 2,128.61 = 871.66 : x
  2. Step 2: Convert to fraction form
    1,420.64/2,128.61 = 871.66/x
  3. Step 3: Cross multiply
    1,420.64x = 2,128.61 × 871.66
  4. Step 4: Simplify right side
    1,420.64x = 1,855,429.03
  5. Step 5: Solve for x
    x = 1,855,429.03/1,420.64
  6. Step 6: Final answer
    x = 1,306.05

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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.