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Finding the Fourth Proportional to 1,309.98, 1,807.78 and 720.50

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Solution

The fourth proportional to 1,309.98, 1,807.78 and 720.50 is: 994.29

Step by Step Solution

  1. Step 1: Write the proportion equation
    1,309.98 : 1,807.78 = 720.50 : x
  2. Step 2: Convert to fraction form
    1,309.98/1,807.78 = 720.50/x
  3. Step 3: Cross multiply
    1,309.98x = 1,807.78 × 720.50
  4. Step 4: Simplify right side
    1,309.98x = 1,302,505.49
  5. Step 5: Solve for x
    x = 1,302,505.49/1,309.98
  6. Step 6: Final answer
    x = 994.29

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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.