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Finding the Fourth Proportional to 911.21, 1,257.61 and 663.66

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Solution

The fourth proportional to 911.21, 1,257.61 and 663.66 is: 915.94

Step by Step Solution

  1. Step 1: Write the proportion equation
    911.21 : 1,257.61 = 663.66 : x
  2. Step 2: Convert to fraction form
    911.21/1,257.61 = 663.66/x
  3. Step 3: Cross multiply
    911.21x = 1,257.61 × 663.66
  4. Step 4: Simplify right side
    911.21x = 834,617.51
  5. Step 5: Solve for x
    x = 834,617.51/911.21
  6. Step 6: Final answer
    x = 915.94

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1.5x scale

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.