The answer is C: multiply by 2
Answer: ∠B = 50°
∠BCD = 40°
<u>Step-by-step explanation:</u>
ACB is a right triangle where ∠A = 40° and ∠C = 90°.
Use the Triangle Sum Theorem for ΔABC to find ∠B:
∠A + ∠B + ∠C = 180°
40° + ∠B + 90° = 180°
∠B + 130° = 180°
∠B = 50°
BCD is a right triangle where ∠B = 50° and ∠D = 90°.
Use the Triangle Sum Theorem for ΔBCD to find ∠C:
∠B + ∠C + ∠D = 180°
50° + ∠C + 90° = 180°
∠C + 140° = 180°
∠C = 40°
Answer:

Step-by-step explanation:
Factor
out of 
Answer: 4.6 km
Step-by-step explanation:
a^1 + b^2 = c^2
2^2 + b^2 = 5^2
4 + b^2 = 25
b = sqrt 25 - 4
b = sqrt 21 = 4.6 km
Answer:
-2
I think it's -2 because you're dividing x by 2 so you'd divide -4 by 2.