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Finding the Fourth Proportional to 1,391.23, 1,919.89 and 770.23

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Solution

The fourth proportional to 1,391.23, 1,919.89 and 770.23 is: 1,062.91

Step by Step Solution

  1. Step 1: Write the proportion equation
    1,391.23 : 1,919.89 = 770.23 : x
  2. Step 2: Convert to fraction form
    1,391.23/1,919.89 = 770.23/x
  3. Step 3: Cross multiply
    1,391.23x = 1,919.89 × 770.23
  4. Step 4: Simplify right side
    1,391.23x = 1,478,756.87
  5. Step 5: Solve for x
    x = 1,478,756.87/1,391.23
  6. Step 6: Final answer
    x = 1,062.91

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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.