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Finding the Fourth Proportional to 990.81, 1,368.77 and 782.37

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Solution

The fourth proportional to 990.81, 1,368.77 and 782.37 is: 1,080.81

Step by Step Solution

  1. Step 1: Write the proportion equation
    990.81 : 1,368.77 = 782.37 : x
  2. Step 2: Convert to fraction form
    990.81/1,368.77 = 782.37/x
  3. Step 3: Cross multiply
    990.81x = 1,368.77 × 782.37
  4. Step 4: Simplify right side
    990.81x = 1,070,880.67
  5. Step 5: Solve for x
    x = 1,070,880.67/990.81
  6. Step 6: Final answer
    x = 1,080.81

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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.