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Finding the Fourth Proportional to 919.95, 1,268.82 and 780.45

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Solution

The fourth proportional to 919.95, 1,268.82 and 780.45 is: 1,076.42

Step by Step Solution

  1. Step 1: Write the proportion equation
    919.95 : 1,268.82 = 780.45 : x
  2. Step 2: Convert to fraction form
    919.95/1,268.82 = 780.45/x
  3. Step 3: Cross multiply
    919.95x = 1,268.82 × 780.45
  4. Step 4: Simplify right side
    919.95x = 990,250.57
  5. Step 5: Solve for x
    x = 990,250.57/919.95
  6. Step 6: Final answer
    x = 1,076.42

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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.