To solve this problem you must apply the proccedure shown below:
1. As you can see in the figure attached, the angle A and the angle B are congruent, which means that both has the same value.
2. Keeping ths on mind you have:
[tex]10x+24=6x+72[/tex]
3. Now, you cam solve for x:
[tex]10x-6x=72-24 \\ 4x=48 \\ x=12[/tex]
4. When you susbtitute the value of x into the equation to calculate the angle A, you obtain:
[tex]A=10(12)+24 \\ A=144[/tex]
The answer is: [tex]144 degrees[/tex]