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Finding the Fourth Proportional to 918.20, 1,266.75 and 638.66

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Solution

The fourth proportional to 918.20, 1,266.75 and 638.66 is: 881.10

Step by Step Solution

  1. Step 1: Write the proportion equation
    918.20 : 1,266.75 = 638.66 : x
  2. Step 2: Convert to fraction form
    918.20/1,266.75 = 638.66/x
  3. Step 3: Cross multiply
    918.20x = 1,266.75 × 638.66
  4. Step 4: Simplify right side
    918.20x = 809,025.72
  5. Step 5: Solve for x
    x = 809,025.72/918.20
  6. Step 6: Final answer
    x = 881.10

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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.