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Finding the Fourth Proportional to 909.56, 1,254.66 and 643.71

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Solution

The fourth proportional to 909.56, 1,254.66 and 643.71 is: 887.95

Step by Step Solution

  1. Step 1: Write the proportion equation
    909.56 : 1,254.66 = 643.71 : x
  2. Step 2: Convert to fraction form
    909.56/1,254.66 = 643.71/x
  3. Step 3: Cross multiply
    909.56x = 1,254.66 × 643.71
  4. Step 4: Simplify right side
    909.56x = 807,637.19
  5. Step 5: Solve for x
    x = 807,637.19/909.56
  6. Step 6: Final answer
    x = 887.95

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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.