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Finding the Fourth Proportional to 1,247.50, 1,720.83 and 780.94

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Solution

The fourth proportional to 1,247.50, 1,720.83 and 780.94 is: 1,077.25

Step by Step Solution

  1. Step 1: Write the proportion equation
    1,247.50 : 1,720.83 = 780.94 : x
  2. Step 2: Convert to fraction form
    1,247.50/1,720.83 = 780.94/x
  3. Step 3: Cross multiply
    1,247.50x = 1,720.83 × 780.94
  4. Step 4: Simplify right side
    1,247.50x = 1,343,860.68
  5. Step 5: Solve for x
    x = 1,343,860.68/1,247.50
  6. Step 6: Final answer
    x = 1,077.25

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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.