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Finding the Fourth Proportional to 399.07, 549.21 and 389.53

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Solution

The fourth proportional to 399.07, 549.21 and 389.53 is: 536.08

Step by Step Solution

  1. Step 1: Write the proportion equation
    399.07 : 549.21 = 389.53 : x
  2. Step 2: Convert to fraction form
    399.07/549.21 = 389.53/x
  3. Step 3: Cross multiply
    399.07x = 549.21 × 389.53
  4. Step 4: Simplify right side
    399.07x = 213,933.77
  5. Step 5: Solve for x
    x = 213,933.77/399.07
  6. Step 6: Final answer
    x = 536.08

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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.