If CD is perpendicular to AB, a right angle is formed by the perpendicular lines at the base of the triangle. If we know that AB is 3 we can divided that by two to use half the triangle and create a right trianle with a base of 1.5 (half of 3) a height of rad 3 now all we have to do is use P-Thags to find AC which is the hypotenuse. After doing 1.5 squared + rad 3 squared = ac squared you will get the answer of AC = 5.25
The vertical line divides triangle ABC into two right angles which are congruent.
DB has length AB/2, which comes out to 3/2. Regard DB as the base of one of the two right triangles. If the height, CD, is √3, then by the Pythagorean Theorem |AC|² = (3/2)² + (√3)².
Thus, |AC| = √( (9/4) + 3 ), or √( (9 + 12)/4 ), or √(21) / 2
