Respuesta :

The measure of angle L
∠M + ∠L + ∠N = 180°
20° + ∠L + 90° = 180°
∠L = 180° - 20° - 90°
∠L = 70°

The trigonometric ratio for NM
tan M = LN/NM
tan 20° = 21/NM
NM = 21/tan 20°

Find the length of NM
NM = 21/tan 20°
NM = 21/0.36397
NM = 57.697
NM = 57.7