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Finding the Fourth Proportional to 427.48, 643.69 and 386.20

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Solution

The fourth proportional to 427.48, 643.69 and 386.20 is: 581.53

Step by Step Solution

  1. Step 1: Write the proportion equation
    427.48 : 643.69 = 386.20 : x
  2. Step 2: Convert to fraction form
    427.48/643.69 = 386.20/x
  3. Step 3: Cross multiply
    427.48x = 643.69 × 386.20
  4. Step 4: Simplify right side
    427.48x = 248,593.08
  5. Step 5: Solve for x
    x = 248,593.08/427.48
  6. Step 6: Final answer
    x = 581.53

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Why These Related Problems?

These problems maintain the same ratio (1.51) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.