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Finding the Fourth Proportional to 991.71, 1,368.16 and 637.57

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Solution

The fourth proportional to 991.71, 1,368.16 and 637.57 is: 879.59

Step by Step Solution

  1. Step 1: Write the proportion equation
    991.71 : 1,368.16 = 637.57 : x
  2. Step 2: Convert to fraction form
    991.71/1,368.16 = 637.57/x
  3. Step 3: Cross multiply
    991.71x = 1,368.16 × 637.57
  4. Step 4: Simplify right side
    991.71x = 872,297.77
  5. Step 5: Solve for x
    x = 872,297.77/991.71
  6. Step 6: Final answer
    x = 879.59

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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.