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Finding the Fourth Proportional to 918.70, 1,378.05 and 814.30

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Solution

The fourth proportional to 918.70, 1,378.05 and 814.30 is: 1,221.45

Step by Step Solution

  1. Step 1: Write the proportion equation
    918.70 : 1,378.05 = 814.30 : x
  2. Step 2: Convert to fraction form
    918.70/1,378.05 = 814.30/x
  3. Step 3: Cross multiply
    918.70x = 1,378.05 × 814.30
  4. Step 4: Simplify right side
    918.70x = 1,122,146.12
  5. Step 5: Solve for x
    x = 1,122,146.12/918.70
  6. Step 6: Final answer
    x = 1,221.45

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Why These Related Problems?

These problems maintain the same ratio (1.50) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.