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Finding the Fourth Proportional to 918.91, 1,378.45 and 260.80

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Solution

The fourth proportional to 918.91, 1,378.45 and 260.80 is: 391.22

Step by Step Solution

  1. Step 1: Write the proportion equation
    918.91 : 1,378.45 = 260.80 : x
  2. Step 2: Convert to fraction form
    918.91/1,378.45 = 260.80/x
  3. Step 3: Cross multiply
    918.91x = 1,378.45 × 260.80
  4. Step 4: Simplify right side
    918.91x = 359,495.66
  5. Step 5: Solve for x
    x = 359,495.66/918.91
  6. Step 6: Final answer
    x = 391.22

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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.