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Finding the Fourth Proportional to 817.72, 1,128.54 and 663.64

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Solution

The fourth proportional to 817.72, 1,128.54 and 663.64 is: 915.89

Step by Step Solution

  1. Step 1: Write the proportion equation
    817.72 : 1,128.54 = 663.64 : x
  2. Step 2: Convert to fraction form
    817.72/1,128.54 = 663.64/x
  3. Step 3: Cross multiply
    817.72x = 1,128.54 × 663.64
  4. Step 4: Simplify right side
    817.72x = 748,944.29
  5. Step 5: Solve for x
    x = 748,944.29/817.72
  6. Step 6: Final answer
    x = 915.89

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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.