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Finding the Fourth Proportional to 991.80, 1,372.14 and 970.20

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Solution

The fourth proportional to 991.80, 1,372.14 and 970.20 is: 1,342.26

Step by Step Solution

  1. Step 1: Write the proportion equation
    991.80 : 1,372.14 = 970.20 : x
  2. Step 2: Convert to fraction form
    991.80/1,372.14 = 970.20/x
  3. Step 3: Cross multiply
    991.80x = 1,372.14 × 970.20
  4. Step 4: Simplify right side
    991.80x = 1,331,250.23
  5. Step 5: Solve for x
    x = 1,331,250.23/991.80
  6. Step 6: Final answer
    x = 1,342.26

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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.