Answer:
s= 15 (nearest integer), 14.8 (to nearest 10ths)
Step-by-step explanation:
here you need to apply the cosine rule,

substituting the values,
u= 13, t=5 and angle S as 60 and solving will give you the answer 14.76 (2 dp)
Answer:
a) 910
b) 828100
c) 144320
Step-by-step explanation:
a. ∑y
This is the sum of all values of y. So

b. (∑y)^2
This is the square of the sum, so the square of 910, that we found in the previous item.
910² = 828100
c. ∑y^2
This is the sum of the squares of each amount spent. So

The answer is 30.25 or as a fraction 30 1/4
The answer would be 59,844 or around that number