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Finding the Fourth Proportional to 427.50, 640.80 and 305.40

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Solution

The fourth proportional to 427.50, 640.80 and 305.40 is: 457.78

Step by Step Solution

  1. Step 1: Write the proportion equation
    427.50 : 640.80 = 305.40 : x
  2. Step 2: Convert to fraction form
    427.50/640.80 = 305.40/x
  3. Step 3: Cross multiply
    427.50x = 640.80 × 305.40
  4. Step 4: Simplify right side
    427.50x = 195,700.32
  5. Step 5: Solve for x
    x = 195,700.32/427.50
  6. Step 6: Final answer
    x = 457.78

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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.