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Finding the Fourth Proportional to 987.48, 1,362.90 and 821.48

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Solution

The fourth proportional to 987.48, 1,362.90 and 821.48 is: 1,133.79

Step by Step Solution

  1. Step 1: Write the proportion equation
    987.48 : 1,362.90 = 821.48 : x
  2. Step 2: Convert to fraction form
    987.48/1,362.90 = 821.48/x
  3. Step 3: Cross multiply
    987.48x = 1,362.90 × 821.48
  4. Step 4: Simplify right side
    987.48x = 1,119,595.09
  5. Step 5: Solve for x
    x = 1,119,595.09/987.48
  6. Step 6: Final answer
    x = 1,133.79

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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.