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Finding the Fourth Proportional to 1,246.86, 1,720.89 and 780.84

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Solution

The fourth proportional to 1,246.86, 1,720.89 and 780.84 is: 1,077.70

Step by Step Solution

  1. Step 1: Write the proportion equation
    1,246.86 : 1,720.89 = 780.84 : x
  2. Step 2: Convert to fraction form
    1,246.86/1,720.89 = 780.84/x
  3. Step 3: Cross multiply
    1,246.86x = 1,720.89 × 780.84
  4. Step 4: Simplify right side
    1,246.86x = 1,343,739.75
  5. Step 5: Solve for x
    x = 1,343,739.75/1,246.86
  6. Step 6: Final answer
    x = 1,077.70

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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.