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Finding the Fourth Proportional to 988.80, 1,362.32 and 689.76

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Solution

The fourth proportional to 988.80, 1,362.32 and 689.76 is: 950.32

Step by Step Solution

  1. Step 1: Write the proportion equation
    988.80 : 1,362.32 = 689.76 : x
  2. Step 2: Convert to fraction form
    988.80/1,362.32 = 689.76/x
  3. Step 3: Cross multiply
    988.80x = 1,362.32 × 689.76
  4. Step 4: Simplify right side
    988.80x = 939,673.84
  5. Step 5: Solve for x
    x = 939,673.84/988.80
  6. Step 6: Final answer
    x = 950.32

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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.