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Finding the Fourth Proportional to 492.64, 678.63 and 399.13

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Solution

The fourth proportional to 492.64, 678.63 and 399.13 is: 549.82

Step by Step Solution

  1. Step 1: Write the proportion equation
    492.64 : 678.63 = 399.13 : x
  2. Step 2: Convert to fraction form
    492.64/678.63 = 399.13/x
  3. Step 3: Cross multiply
    492.64x = 678.63 × 399.13
  4. Step 4: Simplify right side
    492.64x = 270,861.59
  5. Step 5: Solve for x
    x = 270,861.59/492.64
  6. Step 6: Final answer
    x = 549.82

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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.