Given a triangle with sides a, b, c. opposite side c lies the angle alpha. determine the type of angle if a = 8cm, b = 6cm, c = 12cm.

univerkov | November 27, 2020 | education

Given:
ABC – triangle
A = 8 cm
H = 6 cm
C = 12 cm.
Define: Angle type.
Decision:
We use the cosine theorem:
C ^ 2 = A ^ 2 + B ^ 2-2 * A * B * cos (alpha)
144 = 64 + 36-96 * cos (alpha)
14 = -96 * cos (alpha)
cos (alpha) = – 14/96 = -7 / 48, cos of the angle is negative, so the angle is obtuse.

One of the components of a person's success in our time is receiving modern high-quality education, mastering the knowledge, skills and abilities necessary for life in society. A person today needs to study almost all his life, mastering everything new and new, acquiring the necessary professional qualities.