Respuesta :

we know that

cos²(theta)=0.21
sin²(theta)+cos²(theta)=1
sin²(theta)=1-cos²(theta)------> sin²(theta)=1-(0.21)-----> 0.79
 sin(theta)=√0.79
 sin(theta)=0.89

the answer is
the value of  sin(theta) is 0.89

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