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Finding the Fourth Proportional to 1,305.63, 1,958.44 and 428.75

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Solution

The fourth proportional to 1,305.63, 1,958.44 and 428.75 is: 643.12

Step by Step Solution

  1. Step 1: Write the proportion equation
    1,305.63 : 1,958.44 = 428.75 : x
  2. Step 2: Convert to fraction form
    1,305.63/1,958.44 = 428.75/x
  3. Step 3: Cross multiply
    1,305.63x = 1,958.44 × 428.75
  4. Step 4: Simplify right side
    1,305.63x = 839,671.36
  5. Step 5: Solve for x
    x = 839,671.36/1,305.63
  6. Step 6: Final answer
    x = 643.12

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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.