The answer is obtuse
a = 4
b = 28
c = 31
If a² + b² > c² - the angle is acute
If a² + b² < c² - the angle is obtuse
If a² + b² = c² - the angle is right
a² + b² = 4² + 28² = 16 + 784 = 800
c² = 31² = 961
800 < 900
a² + b² < c²
Therefore, the angle is obtuse
Answer:
k = 11b - 8 (easiest to understand)
extra:
k = -8 + 11b
or
11b = -8 - k
etc. ( anything mixing up the components of the equation ).
5cm
13^2-12^2=25
C^2 = 25
C = 5
