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Finding the Fourth Proportional to 918.81, 1,378.44 and 456.80

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Solution

The fourth proportional to 918.81, 1,378.44 and 456.80 is: 685.32

Step by Step Solution

  1. Step 1: Write the proportion equation
    918.81 : 1,378.44 = 456.80 : x
  2. Step 2: Convert to fraction form
    918.81/1,378.44 = 456.80/x
  3. Step 3: Cross multiply
    918.81x = 1,378.44 × 456.80
  4. Step 4: Simplify right side
    918.81x = 629,674.85
  5. Step 5: Solve for x
    x = 629,674.85/918.81
  6. Step 6: Final answer
    x = 685.32

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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.