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Finding the Fourth Proportional to 1,217.79, 1,679.78 and 919.50

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Solution

The fourth proportional to 1,217.79, 1,679.78 and 919.50 is: 1,268.32

Step by Step Solution

  1. Step 1: Write the proportion equation
    1,217.79 : 1,679.78 = 919.50 : x
  2. Step 2: Convert to fraction form
    1,217.79/1,679.78 = 919.50/x
  3. Step 3: Cross multiply
    1,217.79x = 1,679.78 × 919.50
  4. Step 4: Simplify right side
    1,217.79x = 1,544,553.11
  5. Step 5: Solve for x
    x = 1,544,553.11/1,217.79
  6. Step 6: Final answer
    x = 1,268.32

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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.