[tex]\text{ }\frac{9π}{20}\text{ radians (option A)}[/tex]
Explanation:
To convert 81 degrees to radian, we will apply the conversion:
1 π rad = 180°
let the 81° in rad = y
1 π rad = 180°
y = 81°
cross multiply:
1π rad (81) = 180 y
To get y, we divide both sides by 180:
[tex]\begin{gathered} \text{y = }\frac{1\pi rad\text{ }\times\text{ 81}}{180} \\ y\text{ = }\frac{81\text{ }\pi}{180}\text{ = }\frac{9\times9\text{ }\pi}{9\times0}\text{ } \\ 9\text{ is co}mmon\text{ to numerator and denominator. }It\text{ cancels out} \\ y\text{ = }\frac{9\pi}{20} \\ \\ 81\degree\text{ = }\frac{9\pi}{20}\text{ radians (option A)} \end{gathered}[/tex]
