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Finding the Fourth Proportional to 643.04, 886.74 and 421.76

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Solution

The fourth proportional to 643.04, 886.74 and 421.76 is: 581.60

Step by Step Solution

  1. Step 1: Write the proportion equation
    643.04 : 886.74 = 421.76 : x
  2. Step 2: Convert to fraction form
    643.04/886.74 = 421.76/x
  3. Step 3: Cross multiply
    643.04x = 886.74 × 421.76
  4. Step 4: Simplify right side
    643.04x = 373,991.46
  5. Step 5: Solve for x
    x = 373,991.46/643.04
  6. Step 6: Final answer
    x = 581.60

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Why These Related Problems?

These problems maintain the same ratio (1.38) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.