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Finding the Fourth Proportional to 718.51, 991.76 and 621.31

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Solution

The fourth proportional to 718.51, 991.76 and 621.31 is: 857.59

Step by Step Solution

  1. Step 1: Write the proportion equation
    718.51 : 991.76 = 621.31 : x
  2. Step 2: Convert to fraction form
    718.51/991.76 = 621.31/x
  3. Step 3: Cross multiply
    718.51x = 991.76 × 621.31
  4. Step 4: Simplify right side
    718.51x = 616,190.41
  5. Step 5: Solve for x
    x = 616,190.41/718.51
  6. Step 6: Final answer
    x = 857.59

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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.