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Finding the Fourth Proportional to 1,311.63, 1,810.50 and 919.80

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Solution

The fourth proportional to 1,311.63, 1,810.50 and 919.80 is: 1,269.64

Step by Step Solution

  1. Step 1: Write the proportion equation
    1,311.63 : 1,810.50 = 919.80 : x
  2. Step 2: Convert to fraction form
    1,311.63/1,810.50 = 919.80/x
  3. Step 3: Cross multiply
    1,311.63x = 1,810.50 × 919.80
  4. Step 4: Simplify right side
    1,311.63x = 1,665,297.90
  5. Step 5: Solve for x
    x = 1,665,297.90/1,311.63
  6. Step 6: Final answer
    x = 1,269.64

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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.