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Finding the Fourth Proportional to 1,298.75, 1,948.81 and 779.80

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Solution

The fourth proportional to 1,298.75, 1,948.81 and 779.80 is: 1,170.11

Step by Step Solution

  1. Step 1: Write the proportion equation
    1,298.75 : 1,948.81 = 779.80 : x
  2. Step 2: Convert to fraction form
    1,298.75/1,948.81 = 779.80/x
  3. Step 3: Cross multiply
    1,298.75x = 1,948.81 × 779.80
  4. Step 4: Simplify right side
    1,298.75x = 1,519,682.04
  5. Step 5: Solve for x
    x = 1,519,682.04/1,298.75
  6. Step 6: Final answer
    x = 1,170.11

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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.