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Finding the Fourth Proportional to 1,419.80, 2,129.90 and 445.80

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Solution

The fourth proportional to 1,419.80, 2,129.90 and 445.80 is: 668.76

Step by Step Solution

  1. Step 1: Write the proportion equation
    1,419.80 : 2,129.90 = 445.80 : x
  2. Step 2: Convert to fraction form
    1,419.80/2,129.90 = 445.80/x
  3. Step 3: Cross multiply
    1,419.80x = 2,129.90 × 445.80
  4. Step 4: Simplify right side
    1,419.80x = 949,509.42
  5. Step 5: Solve for x
    x = 949,509.42/1,419.80
  6. Step 6: Final answer
    x = 668.76

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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.