Do the following operations with radicals

The missing angle is 21.04°

Step-by-step explanation:

well to start we have to know the relationship between angles, legs and the hypotenuse  in a right triangle

A = ?

a: adjacent= 28

h: hypotenuse = 30

sin A = o/h

cos A= a/h

tan A = o/a

we see that it has (angle, hypotenuse, adjacent)

we look at which meets those data between the sine, cosine and tangent

is the cosine

cos A = a/h

Now we replace the values ​​and solve

cos A = 28 / 30

A = cos^-1 (28 / 30)

A = 21.04°

The missing angle is 21.04°