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Finding the Fourth Proportional to 1,209.80, 1,811.60 and 839.07

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Solution

The fourth proportional to 1,209.80, 1,811.60 and 839.07 is: 1,256.46

Step by Step Solution

  1. Step 1: Write the proportion equation
    1,209.80 : 1,811.60 = 839.07 : x
  2. Step 2: Convert to fraction form
    1,209.80/1,811.60 = 839.07/x
  3. Step 3: Cross multiply
    1,209.80x = 1,811.60 × 839.07
  4. Step 4: Simplify right side
    1,209.80x = 1,520,055.02
  5. Step 5: Solve for x
    x = 1,520,055.02/1,209.80
  6. Step 6: Final answer
    x = 1,256.46

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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.