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Finding the Fourth Proportional to 1,209.80, 1,668.40 and 836.19

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Solution

The fourth proportional to 1,209.80, 1,668.40 and 836.19 is: 1,153.16

Step by Step Solution

  1. Step 1: Write the proportion equation
    1,209.80 : 1,668.40 = 836.19 : x
  2. Step 2: Convert to fraction form
    1,209.80/1,668.40 = 836.19/x
  3. Step 3: Cross multiply
    1,209.80x = 1,668.40 × 836.19
  4. Step 4: Simplify right side
    1,209.80x = 1,395,097.31
  5. Step 5: Solve for x
    x = 1,395,097.31/1,209.80
  6. Step 6: Final answer
    x = 1,153.16

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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.