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Finding the Fourth Proportional to 918.66, 1,266.80 and 639.22

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Solution

The fourth proportional to 918.66, 1,266.80 and 639.22 is: 881.46

Step by Step Solution

  1. Step 1: Write the proportion equation
    918.66 : 1,266.80 = 639.22 : x
  2. Step 2: Convert to fraction form
    918.66/1,266.80 = 639.22/x
  3. Step 3: Cross multiply
    918.66x = 1,266.80 × 639.22
  4. Step 4: Simplify right side
    918.66x = 809,763.90
  5. Step 5: Solve for x
    x = 809,763.90/918.66
  6. Step 6: Final answer
    x = 881.46

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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.