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Finding the Fourth Proportional to 430.25, 643.78 and 257.01

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Solution

The fourth proportional to 430.25, 643.78 and 257.01 is: 384.56

Step by Step Solution

  1. Step 1: Write the proportion equation
    430.25 : 643.78 = 257.01 : x
  2. Step 2: Convert to fraction form
    430.25/643.78 = 257.01/x
  3. Step 3: Cross multiply
    430.25x = 643.78 × 257.01
  4. Step 4: Simplify right side
    430.25x = 165,457.90
  5. Step 5: Solve for x
    x = 165,457.90/430.25
  6. Step 6: Final answer
    x = 384.56

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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.