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Finding the Fourth Proportional to 687.81, 949.20 and 389.01

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Solution

The fourth proportional to 687.81, 949.20 and 389.01 is: 536.85

Step by Step Solution

  1. Step 1: Write the proportion equation
    687.81 : 949.20 = 389.01 : x
  2. Step 2: Convert to fraction form
    687.81/949.20 = 389.01/x
  3. Step 3: Cross multiply
    687.81x = 949.20 × 389.01
  4. Step 4: Simplify right side
    687.81x = 369,248.29
  5. Step 5: Solve for x
    x = 369,248.29/687.81
  6. Step 6: Final answer
    x = 536.85

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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.