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Finding the Fourth Proportional to 1,145.75, 1,581.55 and 680

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Solution

The fourth proportional to 1,145.75, 1,581.55 and 680 is: 938.64

Step by Step Solution

  1. Step 1: Write the proportion equation
    1,145.75 : 1,581.55 = 680 : x
  2. Step 2: Convert to fraction form
    1,145.75/1,581.55 = 680/x
  3. Step 3: Cross multiply
    1,145.75x = 1,581.55 × 680
  4. Step 4: Simplify right side
    1,145.75x = 1,075,450.60
  5. Step 5: Solve for x
    x = 1,075,450.60/1,145.75
  6. Step 6: Final answer
    x = 938.64

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Why These Related Problems?

These problems maintain the same ratio (1.38) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.