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Finding the Fourth Proportional to 399.90, 549.26 and 390.30

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Solution

The fourth proportional to 399.90, 549.26 and 390.30 is: 536.07

Step by Step Solution

  1. Step 1: Write the proportion equation
    399.90 : 549.26 = 390.30 : x
  2. Step 2: Convert to fraction form
    399.90/549.26 = 390.30/x
  3. Step 3: Cross multiply
    399.90x = 549.26 × 390.30
  4. Step 4: Simplify right side
    399.90x = 214,374.23
  5. Step 5: Solve for x
    x = 214,374.23/399.90
  6. Step 6: Final answer
    x = 536.07

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Why These Related Problems?

These problems maintain the same ratio (1.37) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.