Given:
A figure.
To find:
The value of x and y.
Solution:
In triangle ADC, all angles are equal, so it is an equilateral triangle.
We know that, all sides of an equilateral triangle are equal.
...(i)
...(ii)
In triangle ABD,
![\angle BAD=\angle ABD](https://img.qammunity.org/2021/formulas/mathematics/high-school/rofvy8k0elwul7a2ihux5k8o72vciszin4.png)
Base angles are equal, so triangle ABD is an isosceles triangle.
...(iii)
Using (i) and (iii), we get
![AC=BD](https://img.qammunity.org/2021/formulas/mathematics/high-school/gaws52uik3wh1nlrcv4wiey6214wsxp0fo.png)
![5y-4=y+12](https://img.qammunity.org/2021/formulas/mathematics/high-school/d95fieikps5gvsnd6fovphvjg0rnurnyhp.png)
![5y-y=4+12](https://img.qammunity.org/2021/formulas/mathematics/high-school/113ztn7t8ch8yqtebh28yafnqqg630qa40.png)
![4y=16](https://img.qammunity.org/2021/formulas/mathematics/high-school/ms2k80say5t6l5mlbx87nqyragc80yyviz.png)
Divide both sides by 4.
![y=4](https://img.qammunity.org/2021/formulas/mathematics/college/m1jhp5ycpnzo8s03nldtr3h8xv8z64upeu.png)
Putting y=4 in (ii), we get
![3x-5=5(4)-4](https://img.qammunity.org/2021/formulas/mathematics/high-school/sdawtpz8t90sawxdyouni6mbhr3adi5bif.png)
![3x-5=20-4](https://img.qammunity.org/2021/formulas/mathematics/high-school/z9gdwoal9uim9nrtrhh8fbb0vtpeuq1qs1.png)
![3x-5=16](https://img.qammunity.org/2021/formulas/mathematics/high-school/fhmxzo7as6e399e7tdqrolo54td8myx1gv.png)
Adding 5 on both sides, we get
![3x=16+5](https://img.qammunity.org/2021/formulas/mathematics/high-school/7me6is7bdoglr5baqtk6faj5hzn8oq3jg2.png)
![3x=21](https://img.qammunity.org/2021/formulas/mathematics/middle-school/5bt0vqjavl699mywifiquc9fpfxi7ztryq.png)
Divide both sides by 3.
[tex]x=7/tex]
Therefore, the value of x is 7 and the value of y is 4.