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Finding the Fourth Proportional to 918.75, 1,378.89 and 399.14

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Solution

The fourth proportional to 918.75, 1,378.89 and 399.14 is: 599.04

Step by Step Solution

  1. Step 1: Write the proportion equation
    918.75 : 1,378.89 = 399.14 : x
  2. Step 2: Convert to fraction form
    918.75/1,378.89 = 399.14/x
  3. Step 3: Cross multiply
    918.75x = 1,378.89 × 399.14
  4. Step 4: Simplify right side
    918.75x = 550,370.15
  5. Step 5: Solve for x
    x = 550,370.15/918.75
  6. Step 6: Final answer
    x = 599.04

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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.