Consider a non-isosceles triangle △ABC.   Let: ℓ1 be the external angle bisector of ∠A, ℓ2 be the external angle bisector of ∠B and ℓ3 be the external angle bisector of ∠C. a) Explain why ℓ1‖̸BC, ℓ2‖̸AC and ℓ3‖̸AB. Also, Let ℓ1∩BC↔=D, ℓ2∩AC↔=E and ℓ3∩AB↔=F.  Prove that D, E and F are collinear.

4. a) A blue jay, B, is sitting atop of an electrical tower as shown. i) Draw and shade in the angle that would represent the angle of depression of the bluejay as it looks down at an ant, A, on the ground. [T = 1] ii) What is the measure of this angle of depression? [T = 1] b) A pigeon, P is also on the tower as shown. Determine the vertical distance between the two birds (i.e. determine the height of line segment BP). Number your steps for clarity. Round to one decimal place, where needed. P- [T = 3] 40° 25° MathBits.com A 87 feet

Suppose that APQR is isosceles with base QR. Suppose also that m z P= (2x + 56)° and mz Q=(4x+12)°. 7: Find the degree measure of each angle in the triangle. P. (2x + 56). m zP = m zQ = m z R = (4x + 12).