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Finding the Fourth Proportional to 918.72, 1,267.20 and 620.10

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Solution

The fourth proportional to 918.72, 1,267.20 and 620.10 is: 855.31

Step by Step Solution

  1. Step 1: Write the proportion equation
    918.72 : 1,267.20 = 620.10 : x
  2. Step 2: Convert to fraction form
    918.72/1,267.20 = 620.10/x
  3. Step 3: Cross multiply
    918.72x = 1,267.20 × 620.10
  4. Step 4: Simplify right side
    918.72x = 785,790.72
  5. Step 5: Solve for x
    x = 785,790.72/918.72
  6. Step 6: Final answer
    x = 855.31

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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.