Answer:
15th term = 116
Step-by-step explanation:
a= 4
Sum of an A.P = n/2 {2a + (n-1)d}
sum of first five term is equal to one-fourth of the sum of the next five term
5/2{ 2*4 + (5-1)d} = 1/4 × 10/2{2*4 + (10-1)d
5/2 {8 + 4d} = 1/4 × 5{ 8 + 9d}
40/2 + 20/2d = 1/4{ 40 + 45d)
20 + 10d= 40/4 + 45/4d
20 + 10d = 10 + 45/4d
20 - 10 = 45/4d - 10d
10 =45d - 40d /4
10 = 5/4d
Divide both sides by 5/4
10 ÷5/4 = d
10×4/5 = d
40/5 = d
8 = d
d= 8
Find the 15th term
15th term = a + (n-1)d
= 4 + (15-1)8
= 4 + (14)8
= 4 + 112
= 116
The 15th term is 116
P(the students she selects are both boys)=7/12×5/10=35/120=7/24
Answer:
(a) the new angle the ladder makes with the ground is 
(b) the ladder slipped back about 5 meters
Step-by-step explanation:
Notice that the ladder doesn't change its length in the process.
So let's start from the initial situation , finding the distance from the ground at which the ladder touches the wall when the angle with the ground is 70^o. Notice that this situation is represented by a right angle triangle with the right angle between the wall and the ground (see attached image), and that we can use the sine function to find the side opposite to the 70 degree angle:

therefore 9.4 meters is approximately the height at which the ladder touches the wall initially.
Now, if the tip of the ladder goes down the wall 4 meters, it is now at 9.4 m - 4 m = 5.4 m from the ground. We can therefore use again the sine function to solve for the new angle:

To answer the second question we need to find the original distance from the wall that the bottom of the ladder was originally, and for that we can use the cosine function:

Now fro the new position of the bottom of the ladder relative to the wall:

then the difference in between those two distances is what we need:
8.4 m - 3.4 m = 5 m
Answer:
4th
Step-by-step explanation:
(-1,3)
here is the answer
Answer:
B
Step-by-step explanation:
The measure of the chord- chord angle ABC is half the sum of the arcs intercepted by the angle and its vertical angle, that is
∠ ABC = 0.5( 82 + 44)° = 0.5 × 126° = 63° → B