The diameter of circle c is 18 cm. chord ad is the same length as a radius. use this information, the diagram, and your experiences in geometry this semester to answer these questions. a) what are the measures of the angles bda and dba? . b) what is the sine of angle dba? c) find the length of arc ab to the nearest hundredth. d) how does the length of arc ad compare to the length of arc ab? e) if fe = 1/2 bd, then what is the degree measure of arc ef?

A ) ∠ BDA = 60°
∠DBA = 30°
B ) sin (∠DBA ) = sin 30° = 1/2
C ) arc AB = 1/3 · 2 r π = 1/3 · 18 π = 6 π = 6 · 3.14 = 18.84 cm
D ) arc AD : arc AB = 1 : 2
E ) Degree measure of an arc is equal to the measure of the central angle that intercepts the arc. The degree measure is 60° ( F E = 9 cm, r = 9 cm ). 

Okay so for every triangle has three angles that always add up to 180 degrees. and to tell the difference between whether they are secure, right or obtuse is that acute: has one angle that is less than 90 degrees. right triangle means there is at least one angle that is exactly 90 degrees. and an obtuse angle has an angle that is bigger than 180 degrees. i’ll do #13 as an example: 13. 40 and 50 so if every triangle has 180 degrees 40+50= 90 degrees then180-90= 90 degrees so the third angle is 90 degrees and because this triangle has a 90 degree angle it means it is a right triangle

Hello!

the answer is:

the correct option is the option b.

why?

to calculate the surface area of the right cylinder, we need to use the following formula:

from the picture we know that:

so, substituting and calculting we have:

hence, we have that the correct option is the option b.

have a nice day!