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Finding the Fourth Proportional to 989.91, 1,365.53 and 779.31

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Solution

The fourth proportional to 989.91, 1,365.53 and 779.31 is: 1,075.01

Step by Step Solution

  1. Step 1: Write the proportion equation
    989.91 : 1,365.53 = 779.31 : x
  2. Step 2: Convert to fraction form
    989.91/1,365.53 = 779.31/x
  3. Step 3: Cross multiply
    989.91x = 1,365.53 × 779.31
  4. Step 4: Simplify right side
    989.91x = 1,064,167.29
  5. Step 5: Solve for x
    x = 1,064,167.29/989.91
  6. Step 6: Final answer
    x = 1,075.01

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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.