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Finding the Fourth Proportional to 430.02, 643.43 and 256.78

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Solution

The fourth proportional to 430.02, 643.43 and 256.78 is: 384.21

Step by Step Solution

  1. Step 1: Write the proportion equation
    430.02 : 643.43 = 256.78 : x
  2. Step 2: Convert to fraction form
    430.02/643.43 = 256.78/x
  3. Step 3: Cross multiply
    430.02x = 643.43 × 256.78
  4. Step 4: Simplify right side
    430.02x = 165,219.96
  5. Step 5: Solve for x
    x = 165,219.96/430.02
  6. Step 6: Final answer
    x = 384.21

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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.