Answer:
line bc is 8.66 units and angle A is 60 degrees
Step-by-step explanation:
bc^2 + 5^2 = 10^2
bc^2 = 100 - 25
bc^2 = 75
bc = 8.660 units
sum of interior angles = 180 deg
30 deg + 90 deg + angle a = 180 deg
120 deg + angle a = 180 deg
angle a = 180 - 120
angle a = 60 deg
