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Finding the Fourth Proportional to 399.40, 549.78 and 377.80

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Solution

The fourth proportional to 399.40, 549.78 and 377.80 is: 520.05

Step by Step Solution

  1. Step 1: Write the proportion equation
    399.40 : 549.78 = 377.80 : x
  2. Step 2: Convert to fraction form
    399.40/549.78 = 377.80/x
  3. Step 3: Cross multiply
    399.40x = 549.78 × 377.80
  4. Step 4: Simplify right side
    399.40x = 207,706.88
  5. Step 5: Solve for x
    x = 207,706.88/399.40
  6. Step 6: Final answer
    x = 520.05

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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.