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Finding the Fourth Proportional to 1,039.12, 1,555.77 and 782.80

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Solution

The fourth proportional to 1,039.12, 1,555.77 and 782.80 is: 1,172.01

Step by Step Solution

  1. Step 1: Write the proportion equation
    1,039.12 : 1,555.77 = 782.80 : x
  2. Step 2: Convert to fraction form
    1,039.12/1,555.77 = 782.80/x
  3. Step 3: Cross multiply
    1,039.12x = 1,555.77 × 782.80
  4. Step 4: Simplify right side
    1,039.12x = 1,217,856.76
  5. Step 5: Solve for x
    x = 1,217,856.76/1,039.12
  6. Step 6: Final answer
    x = 1,172.01

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Why These Related Problems?

These problems maintain the same ratio (1.50) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.