Respuesta :

the complete question in the attached figure

we know that
 tan R°=opposite side angle R/adjacent side angle R
opposite side angle R=72 units
adjacent side angle R=25 units
so
 tan R°=72/25
R=arc tan (72/25)---------> R=70.85°-------> R=70.9°

the answer is 
R=70.9°
Ver imagen calculista