1) Given these two congruent triangles, we have a right triangle. So we can use the metric relations for the right triangle
2) So we can write for the triangle ΔDBC, let's find the leg DB
a²=b²+c²
BC²=DC²+DB² BC is the hypotenuse from ΔDBC
15²= 12² +DB²
225= 144 +DB² Flip it
DB²=225-144
√DB²=√81
DB =9
If AB = 14, DB = 9 then DA = 14-9 DA = 5
Now let's find the hypotenuse from
