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Finding the Fourth Proportional to 1,089.80, 1,633.44 and 782.40

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Solution

The fourth proportional to 1,089.80, 1,633.44 and 782.40 is: 1,172.70

Step by Step Solution

  1. Step 1: Write the proportion equation
    1,089.80 : 1,633.44 = 782.40 : x
  2. Step 2: Convert to fraction form
    1,089.80/1,633.44 = 782.40/x
  3. Step 3: Cross multiply
    1,089.80x = 1,633.44 × 782.40
  4. Step 4: Simplify right side
    1,089.80x = 1,278,003.46
  5. Step 5: Solve for x
    x = 1,278,003.46/1,089.80
  6. Step 6: Final answer
    x = 1,172.70

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Why These Related Problems?

These problems maintain the same ratio (1.50) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.