Yep, this one seems sneaky and confusing. But it's not so bad if you remember the things you learned about parallel lines. (It can't be too tough ... I learned them
in 1954 and I still know how to use them.)
Look at the picture. Line ' l ' is parallel to line ' m ', and the horizontal line on the bottom (which is not labeled) is a transversal that cuts the parallel lines.
Did you learn that interior angles on the same side of the transversal are equal ?
I'm sure you did, although it may have a new name nowadays.
Anyway, with the help of that 'tool', angle-'B' and angle-'D' are equal. So . . .
(angle-A + angle-B) = 120
angle-B = 65
angle-A = 120 - 65 = <u>55 degrees</u>.
Answer:
92.31 km
Step-by-step explanation:
Combined speed = 50+80
= 130 km/hour
Time = 100/130 = 10/13 hours to collide
Speed × time = distance
distance = 10/13 × 120
= 92.30769231 km
Part 1: The general form for this matches y^2 = -4cx, which implies that this opens to the left. (Imagine assigning any value of y, whether positive or negative, which would result in a positive left-hand value. Then to match this sign, the value of x must be negative so that the right-hand side becomes positive as well.)
Part 2: The distance from the vertex to the directrix is given by c. This equation has its vertex at the origin (0, 0). If it opens to the left, the directrix is a vertical line to the right of the origin. This equation is y^2 = -4(1/2)x, so c = 1/2, and the directrix has the equation x = 1/2.
Part 3: The focus is inside the parabola, but it is the same distance from the vertex as the directrix. This distance is 1/2 units, and it will be to the left of the vertex. So the focus is at (-1/2, 0).
Answer:
.009
Step-by-step explanation:
