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Finding the Fourth Proportional to 864.64, 1,190.28 and 642.88

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Solution

The fourth proportional to 864.64, 1,190.28 and 642.88 is: 885.00

Step by Step Solution

  1. Step 1: Write the proportion equation
    864.64 : 1,190.28 = 642.88 : x
  2. Step 2: Convert to fraction form
    864.64/1,190.28 = 642.88/x
  3. Step 3: Cross multiply
    864.64x = 1,190.28 × 642.88
  4. Step 4: Simplify right side
    864.64x = 765,207.21
  5. Step 5: Solve for x
    x = 765,207.21/864.64
  6. Step 6: Final answer
    x = 885.00

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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.