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Finding the Fourth Proportional to 987.52, 1,360.52 and 821.21

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Solution

The fourth proportional to 987.52, 1,360.52 and 821.21 is: 1,131.39

Step by Step Solution

  1. Step 1: Write the proportion equation
    987.52 : 1,360.52 = 821.21 : x
  2. Step 2: Convert to fraction form
    987.52/1,360.52 = 821.21/x
  3. Step 3: Cross multiply
    987.52x = 1,360.52 × 821.21
  4. Step 4: Simplify right side
    987.52x = 1,117,272.63
  5. Step 5: Solve for x
    x = 1,117,272.63/987.52
  6. Step 6: Final answer
    x = 1,131.39

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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.