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Finding the Fourth Proportional to 1,271.40, 1,908.30 and 785.40

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Solution

The fourth proportional to 1,271.40, 1,908.30 and 785.40 is: 1,178.84

Step by Step Solution

  1. Step 1: Write the proportion equation
    1,271.40 : 1,908.30 = 785.40 : x
  2. Step 2: Convert to fraction form
    1,271.40/1,908.30 = 785.40/x
  3. Step 3: Cross multiply
    1,271.40x = 1,908.30 × 785.40
  4. Step 4: Simplify right side
    1,271.40x = 1,498,778.82
  5. Step 5: Solve for x
    x = 1,498,778.82/1,271.40
  6. Step 6: Final answer
    x = 1,178.84

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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.