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Finding the Fourth Proportional to 1,639.40, 2,458.86 and 485

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Solution

The fourth proportional to 1,639.40, 2,458.86 and 485 is: 727.43

Step by Step Solution

  1. Step 1: Write the proportion equation
    1,639.40 : 2,458.86 = 485 : x
  2. Step 2: Convert to fraction form
    1,639.40/2,458.86 = 485/x
  3. Step 3: Cross multiply
    1,639.40x = 2,458.86 × 485
  4. Step 4: Simplify right side
    1,639.40x = 1,192,547.10
  5. Step 5: Solve for x
    x = 1,192,547.10/1,639.40
  6. Step 6: Final answer
    x = 727.43

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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.