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Finding the Fourth Proportional to 420.64, 630 and 378.40

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Solution

The fourth proportional to 420.64, 630 and 378.40 is: 566.74

Step by Step Solution

  1. Step 1: Write the proportion equation
    420.64 : 630 = 378.40 : x
  2. Step 2: Convert to fraction form
    420.64/630 = 378.40/x
  3. Step 3: Cross multiply
    420.64x = 630 × 378.40
  4. Step 4: Simplify right side
    420.64x = 238,392
  5. Step 5: Solve for x
    x = 238,392/420.64
  6. Step 6: Final answer
    x = 566.74

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Why These Related Problems?

These problems maintain the same ratio (1.50) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.