Solution:
You have presented a right-angled triangle ABC with an altitude BD from the right angle B to the hypotenuse AC, creating two smaller right-angled triangles, ABD and BDC. You have provided several pieces of information:1. The angle $$ \angle ABC = 15^\circ $$2. The angle $$ \angle BAD = 45^\circ $$3. The length of BD is equal to that of DC, i.e., $$ BD = DC $$You've asked to solve for the value of y, where y is the length of AC. But there's no direct indication of how the lengths on the triangle relate to y. The given angles and conditions suggest that we can calculate the length of AC using trigonometric ratios. Since triangle ABD and BDC are both isosceles and right-angled, we know several relationships:1. $$ AB = BD $$ (since $$ \angle BAD = 45^\circ $$ it is an isosceles right-angled triangle, so the two non-hypotenuse sides are equal)2. $$ BD = DC $$ (given)3. Therefore, $$ AB = BD = BC $$, and those lengths are all equal to each other.To find y, we need to use these relationships and the fact that $$ \angle ABC = 15^\circ $$. We'll use the trigonometric identity for the sine of a 15-degree angle, as we're given $$ \angle ABC $$ and we have a right-angled triangle.In right-angled triangle ABC:$$\sin(15^\circ) = \frac{AB}{AC} = \frac{BD}{AC}$$We know that $$ \sin(15^\circ) $$ can be expressed using the half-angle identity:$$\sin(15^\circ) = \sin(30^\circ / 2) = \sqrt{\frac{1 - \cos(30^\circ)}{2}} = \sqrt{\frac{1 - \sqrt{3}/2}{2}}$$Simplifying the expression under the square root gives us:$$\sin(15^\circ) = \sqrt{\frac{2 - \sqrt{3}}{4}}$$Using this identity, we can relate the length of AC to BD:$$\sqrt{\frac{2 - \sqrt{3}}{4}} = \frac{BD}{AC}$$Since $$ BD = BC $$ and $$ BC = AB $$, let's denote the length of BD (also AB and BC) as x. Then the above equation becomes:$$\sqrt{\frac{2 - \sqrt{3}}{4}} = \frac{x}{y}$$We can solve for y by multiplying both sides by y and dividing by $$ \sqrt{\frac{2 - \sqrt{3}}{4}} $$:$$y = \frac{x}{\sqrt{\frac{2 - \sqrt{3}}{4}}}$$However, we have not been provided the actual numerical length for x (BD, AB, or BC), so we cannot provide a numerical solution for y without additional information. If you have a length for BD, AB, or BC, you can substitute that value into the equation to solve for y.