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Finding the Fourth Proportional to 991.04, 1,367.60 and 642.08

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Solution

The fourth proportional to 991.04, 1,367.60 and 642.08 is: 886.05

Step by Step Solution

  1. Step 1: Write the proportion equation
    991.04 : 1,367.60 = 642.08 : x
  2. Step 2: Convert to fraction form
    991.04/1,367.60 = 642.08/x
  3. Step 3: Cross multiply
    991.04x = 1,367.60 × 642.08
  4. Step 4: Simplify right side
    991.04x = 878,108.61
  5. Step 5: Solve for x
    x = 878,108.61/991.04
  6. Step 6: Final answer
    x = 886.05

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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.