For the given vectors
and 
The dot product of vectors a and b is defined as = 
So, 

= -16+12
= -4
Answer:
If there is 1 at the top, then you have 1, then 2, then 3, etc.
total number of oranges equals:
1 + 2 + 3 + ... + 16 + 17 + 18 <-- stop at 18 because this is the number of oranges at the base
You can use the formula:
sum of first n numbers = n*(n + 1)/2
-->
18*19/2 = 9*19 = 171
or you can figure it out (basically derive the above formula):
you have:
1 + 18 = 19
2 + 17 = 19
3 + 16 = 19
...
How many pairs do you have? Well, it's just the number of numbers: 1-18 = 18 numbers (divide by 2) = 9 pairs)
9 pairs of 19 = 9 * 19 = 171
Hope this helps!
Step-by-step explanation:
Answer:It should be x=1 not sure thought.
Step-by-step explanation:
Answer: The correct option are B, C and D.
Explanation:
The law of sine states that,

Where A, B, C are interior angles of the triangle and a, b, c are sides opposite sides of these angles respectively as shown in below figure. Only AAS or SSA types problems can be solved by using Law of sine.
Since we need the combination of two sides and one angle or two angles and one side.
In option A, the two consecutive angles are known and a side which makes the second angle with base side is known, therefore the first angle is opposite to the given side, so the law of sine can be used for AAS problems.
Therefore, option A is incorrect.
In option B a side is known and two inclined angle on that line are known. But to use Law of sine we want the line and angle which in not inclined on that line, therefore the ASA problem can not be solved by Law of sine and the option B is correct.
In option C two sides and their inclined angle is known. But to use Law of sine we want the side and angle which in not inclined on that line, therefore the SAS problem can not be solved by Law of sine and the option C is correct.
In option D three sides are given but any angle is not given, therefore the SSS problem can not be solved by Law of sine and the option D is correct.