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Finding the Fourth Proportional to 821.64, 1,134.72 and 691.68

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Solution

The fourth proportional to 821.64, 1,134.72 and 691.68 is: 955.24

Step by Step Solution

  1. Step 1: Write the proportion equation
    821.64 : 1,134.72 = 691.68 : x
  2. Step 2: Convert to fraction form
    821.64/1,134.72 = 691.68/x
  3. Step 3: Cross multiply
    821.64x = 1,134.72 × 691.68
  4. Step 4: Simplify right side
    821.64x = 784,863.13
  5. Step 5: Solve for x
    x = 784,863.13/821.64
  6. Step 6: Final answer
    x = 955.24

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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.