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Finding the Fourth Proportional to 990.40, 1,366.23 and 636.23

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Solution

The fourth proportional to 990.40, 1,366.23 and 636.23 is: 877.66

Step by Step Solution

  1. Step 1: Write the proportion equation
    990.40 : 1,366.23 = 636.23 : x
  2. Step 2: Convert to fraction form
    990.40/1,366.23 = 636.23/x
  3. Step 3: Cross multiply
    990.40x = 1,366.23 × 636.23
  4. Step 4: Simplify right side
    990.40x = 869,236.51
  5. Step 5: Solve for x
    x = 869,236.51/990.40
  6. Step 6: Final answer
    x = 877.66

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1.5x scale

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.