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Finding the Fourth Proportional to 989.62, 1,365.05 and 779.57

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Solution

The fourth proportional to 989.62, 1,365.05 and 779.57 is: 1,075.32

Step by Step Solution

  1. Step 1: Write the proportion equation
    989.62 : 1,365.05 = 779.57 : x
  2. Step 2: Convert to fraction form
    989.62/1,365.05 = 779.57/x
  3. Step 3: Cross multiply
    989.62x = 1,365.05 × 779.57
  4. Step 4: Simplify right side
    989.62x = 1,064,159.95
  5. Step 5: Solve for x
    x = 1,064,159.95/989.62
  6. Step 6: Final answer
    x = 1,075.32

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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.