Respuesta :

that is adjacent and huptonuse
soh cah toah
so that is cos

cos(x)=15/21
so tehrfor
cos⁻¹(15/21)=x
where cos⁻¹ means inverse not 1/cos

use your calculator to evaluate cos⁻¹(15/21) in degrees

it is about 44.4153 degres, rounded to 44 degrees