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Finding the Fourth Proportional to 1,311.23, 1,808.71 and 779.92

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Solution

The fourth proportional to 1,311.23, 1,808.71 and 779.92 is: 1,075.81

Step by Step Solution

  1. Step 1: Write the proportion equation
    1,311.23 : 1,808.71 = 779.92 : x
  2. Step 2: Convert to fraction form
    1,311.23/1,808.71 = 779.92/x
  3. Step 3: Cross multiply
    1,311.23x = 1,808.71 × 779.92
  4. Step 4: Simplify right side
    1,311.23x = 1,410,642.63
  5. Step 5: Solve for x
    x = 1,410,642.63/1,311.23
  6. Step 6: Final answer
    x = 1,075.81

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Why These Related Problems?

These problems maintain the same ratio (1.38) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.