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Finding the Fourth Proportional to 918.81, 1,378.21 and 260.69

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Solution

The fourth proportional to 918.81, 1,378.21 and 260.69 is: 391.03

Step by Step Solution

  1. Step 1: Write the proportion equation
    918.81 : 1,378.21 = 260.69 : x
  2. Step 2: Convert to fraction form
    918.81/1,378.21 = 260.69/x
  3. Step 3: Cross multiply
    918.81x = 1,378.21 × 260.69
  4. Step 4: Simplify right side
    918.81x = 359,285.56
  5. Step 5: Solve for x
    x = 359,285.56/918.81
  6. Step 6: Final answer
    x = 391.03

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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.