In right △ABC , the right angle is at C, m∠A=30 degrees , and AC=7√5 units.
What is the perimeter of △ABC
B
C 7√5 A
We have a 30-60-90 right triangle
Angle CBA = 60°
Angle BCA = 90°.....the side opposite this has the length 2 ( 7√5) / √3 = 14√5 / √3 = 14√15 / 3
Angle BAC = 30° ....the side opposite this has the length 7√15/3
So....the perimeter =
7√5 + (√15/3) (14 + 7) =
7√5 + (√15/3)(21) =
7√5 + 7√15 =
7 (√5 + √15) units ≈ 42.76 units