A '_-' Ill 9-4 Additional Practice Parabolas in the Coordinate Plane Find the vertex of each parabola focus: (2, 9); directrix: y = 1 2. focus: (2, -2); directrix: y = 0 Find the vertex, focus, and directrix of each parabola. _ _ .1- _ 2 . = i _ 2 @y 4_16(x 7) 4 y+7 12(x 6) 1 (9}/_3=2'4(x+3)2 6-y5=(x+3)2 Write an equation of each parabola with the given focus and vertex. @focus: (4, 9); vertex: (4, 5) 8. focus: (2, 4); vertex: (2, 0) @focus: (7, 10); vertex: (7, 4) 10. focus: (5, 3); vertex: (5, 6) Use the graph of the parabola to answer each question. 11; What is the vertex of the parabola? 12. What is p? 13. What is the focus of the parabola? 14. What is the directrix of the parabola? 15. If the vertex of a parabola is (a, b) and the focus is (a, c), What is the equation of the parabola? 'A parabolic reflector for a microphone has the microphone element at the focus, which is 3 in. from the vertex of the reflector. If you consider the vertex to be at the origin, what is the equation of the parabola? Name enVision Goometry SawwasRealize.com 10-2 Additional Practice Lines Tangent to a Circle In Exercises 1 and 2, segment AB is tangent to OC. Find each value. 1. AB or 2. mZABC In Exercises 3-5, find each value. 4x - 4 3. JF and GF are tangent to OH. What is HJ? H x +1 3x 4. KL, LM, MN, and KN are tangent to the circle. What is the perimeter of KLMN? 10 N 6 5. RP and TP are tangent to oS and OW. R What is RP? 20 W 81 66 6. Construct a tangent to oA that passes through B. A . . B 7. If two segments share an endpoint and are tangent to the same circle at their other endpoints, what must be true of the segments? 8. A marble with radius / rolls in a L-shaped track. How far is the center of the marble from the corner of the track? Y enVision TM Geometry . Teaching Resources