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Finding the Fourth Proportional to 1,313.66, 1,969.98 and 389

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Solution

The fourth proportional to 1,313.66, 1,969.98 and 389 is: 583.35

Step by Step Solution

  1. Step 1: Write the proportion equation
    1,313.66 : 1,969.98 = 389 : x
  2. Step 2: Convert to fraction form
    1,313.66/1,969.98 = 389/x
  3. Step 3: Cross multiply
    1,313.66x = 1,969.98 × 389
  4. Step 4: Simplify right side
    1,313.66x = 766,322.22
  5. Step 5: Solve for x
    x = 766,322.22/1,313.66
  6. Step 6: Final answer
    x = 583.35

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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.