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Finding the Fourth Proportional to 1,369.88, 1,890.43 and 780.75

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Solution

The fourth proportional to 1,369.88, 1,890.43 and 780.75 is: 1,077.43

Step by Step Solution

  1. Step 1: Write the proportion equation
    1,369.88 : 1,890.43 = 780.75 : x
  2. Step 2: Convert to fraction form
    1,369.88/1,890.43 = 780.75/x
  3. Step 3: Cross multiply
    1,369.88x = 1,890.43 × 780.75
  4. Step 4: Simplify right side
    1,369.88x = 1,475,953.22
  5. Step 5: Solve for x
    x = 1,475,953.22/1,369.88
  6. Step 6: Final answer
    x = 1,077.43

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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.