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Finding the Fourth Proportional to 811.94, 1,119.75 and 645.88

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Solution

The fourth proportional to 811.94, 1,119.75 and 645.88 is: 890.74

Step by Step Solution

  1. Step 1: Write the proportion equation
    811.94 : 1,119.75 = 645.88 : x
  2. Step 2: Convert to fraction form
    811.94/1,119.75 = 645.88/x
  3. Step 3: Cross multiply
    811.94x = 1,119.75 × 645.88
  4. Step 4: Simplify right side
    811.94x = 723,224.13
  5. Step 5: Solve for x
    x = 723,224.13/811.94
  6. Step 6: Final answer
    x = 890.74

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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.