In the figure, we can consider that the base is the side that mesures 12 in and that the height is the side that measures 15 in, since that sides are perpendicular. So, we just need to use the given formula:
Hence, the area of the triangle is 90 in² (B).
Answer:
89.1° or -1.4°
Step-by-step explanation:
1. Location:
You are on the Mont-Saint-Jean escarpment, near the Belgian town of Waterloo.
The French troops are about 50 m below you and 1.2 km distant.
2. Finding the firing angle
Data:
R = 1200 m
u = 600 m/s
h = -50 m (the height of the target)
a = 9.8 m/s²
We have two conditions.
Horizontal distance
(1) 1200 = 600t cosθ
Vertical distance
(2) -50 = 600t sinθ - 4.9t²
Divide each side of (1) by 600cosθ.
Substitute (3) into (2)
Recall that
(5) sec²θ = 1/cos²θ = tan²θ + 1
Substitute (5) into (4)
Set up a quadratic equation
Solve for θ
Use the quadratic formula.
tanθ = 61.249 or -0.025
θ = arctan(61.249) = 89.1° or
θ = arctan(-0.025) = -1.4°