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Finding the Fourth Proportional to 400.79, 553.08 and 389

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Solution

The fourth proportional to 400.79, 553.08 and 389 is: 536.81

Step by Step Solution

  1. Step 1: Write the proportion equation
    400.79 : 553.08 = 389 : x
  2. Step 2: Convert to fraction form
    400.79/553.08 = 389/x
  3. Step 3: Cross multiply
    400.79x = 553.08 × 389
  4. Step 4: Simplify right side
    400.79x = 215,148.12
  5. Step 5: Solve for x
    x = 215,148.12/400.79
  6. Step 6: Final answer
    x = 536.81

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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.