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Finding the Fourth Proportional to 1,309.80, 1,807.60 and 720.35

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Solution

The fourth proportional to 1,309.80, 1,807.60 and 720.35 is: 994.12

Step by Step Solution

  1. Step 1: Write the proportion equation
    1,309.80 : 1,807.60 = 720.35 : x
  2. Step 2: Convert to fraction form
    1,309.80/1,807.60 = 720.35/x
  3. Step 3: Cross multiply
    1,309.80x = 1,807.60 × 720.35
  4. Step 4: Simplify right side
    1,309.80x = 1,302,104.66
  5. Step 5: Solve for x
    x = 1,302,104.66/1,309.80
  6. Step 6: Final answer
    x = 994.12

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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.