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Finding the Fourth Proportional to 1,212.80, 1,672.26 and 840.07

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Solution

The fourth proportional to 1,212.80, 1,672.26 and 840.07 is: 1,158.32

Step by Step Solution

  1. Step 1: Write the proportion equation
    1,212.80 : 1,672.26 = 840.07 : x
  2. Step 2: Convert to fraction form
    1,212.80/1,672.26 = 840.07/x
  3. Step 3: Cross multiply
    1,212.80x = 1,672.26 × 840.07
  4. Step 4: Simplify right side
    1,212.80x = 1,404,807.10
  5. Step 5: Solve for x
    x = 1,404,807.10/1,212.80
  6. Step 6: Final answer
    x = 1,158.32

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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.