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Finding the Fourth Proportional to 909.95, 1,253.39 and 643.93

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Solution

The fourth proportional to 909.95, 1,253.39 and 643.93 is: 886.96

Step by Step Solution

  1. Step 1: Write the proportion equation
    909.95 : 1,253.39 = 643.93 : x
  2. Step 2: Convert to fraction form
    909.95/1,253.39 = 643.93/x
  3. Step 3: Cross multiply
    909.95x = 1,253.39 × 643.93
  4. Step 4: Simplify right side
    909.95x = 807,089.07
  5. Step 5: Solve for x
    x = 807,089.07/909.95
  6. Step 6: Final answer
    x = 886.96

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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.