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Finding the Fourth Proportional to 1,289.87, 1,780.05 and 722.75

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Solution

The fourth proportional to 1,289.87, 1,780.05 and 722.75 is: 997.41

Step by Step Solution

  1. Step 1: Write the proportion equation
    1,289.87 : 1,780.05 = 722.75 : x
  2. Step 2: Convert to fraction form
    1,289.87/1,780.05 = 722.75/x
  3. Step 3: Cross multiply
    1,289.87x = 1,780.05 × 722.75
  4. Step 4: Simplify right side
    1,289.87x = 1,286,522.24
  5. Step 5: Solve for x
    x = 1,286,522.24/1,289.87
  6. Step 6: Final answer
    x = 997.41

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1.5x scale

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.