Hello!
The equation for a circle is

r is the radius
To find the radius we take the square root of the number in the radius spot
sqrt169 = 13
The answer is 13
Hope this helps!
As I've shown on picture that I attached:
∠ADC=∠ADB+∠BDC⇒134=5x+4+7x-2
12x+2=134
12x=132⇒x=132/12
x=11
Angle BDC measure 7x-2=7*11-2⇒∠BDC=75.
In order to find the answer of the given problem above, we need to make the solution below:
Given: 2/3 of an hour = practice each day
2/3 of an hour is equivalent to 40 minutes
And per week, there are 7 days. So we will multiply 40 minutes by 7, and the result is 280 minutes. Since there are 60 minutes in an hour, we divide 280 by 60 and we get 4.67 hours. Therefore, each week, you would get 4.67 hours of practice on playing a musical instrument.