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Finding the Fourth Proportional to 661.68, 911.16 and 645.36

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Solution

The fourth proportional to 661.68, 911.16 and 645.36 is: 888.69

Step by Step Solution

  1. Step 1: Write the proportion equation
    661.68 : 911.16 = 645.36 : x
  2. Step 2: Convert to fraction form
    661.68/911.16 = 645.36/x
  3. Step 3: Cross multiply
    661.68x = 911.16 × 645.36
  4. Step 4: Simplify right side
    661.68x = 588,026.22
  5. Step 5: Solve for x
    x = 588,026.22/661.68
  6. Step 6: Final answer
    x = 888.69

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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.