Answer:
For right angle triangle,
we use Pythagoras theorem that is:

c = 
For question 1:
c = ?
a = 40
b = 9
putting them in formula,
c = 
c = 41
For question 2:
c = ?
a = 12
b = 13
putting them in formula,
c = 
c = approximately 17.69181
For question 3:
c = 35
a = 20
b = ?
putting them in formula,


1225 = 400 + 
= 1225 - 400
= 825

b = 5 
For question 4:
c = 37
a = 20
b = ?
putting them in formula,


1369 = 400 + 
= 1369 - 400
= 969
Taking square root on both sides
b = 31.12
Hope it helps.
The last one represents a function ..
Answer and Step-by-step explanation:
(a) Given that x and y is even, we want to prove that xy is also even.
For x and y to be even, x and y have to be a multiple of 2. Let x = 2k and y = 2p where k and p are real numbers. xy = 2k x 2p = 4kp = 2(2kp). The product is a multiple of 2, this means the number is also even. Hence xy is even when x and y are even.
(b) in reality, if an odd number multiplies and odd number, the result is also an odd number. Therefore, the question is wrong. I assume they wanted to ask for the proof that the product is also odd. If that's the case, then this is the proof:
Given that x and y are odd, we want to prove that xy is odd. For x and y to be odd, they have to be multiples of 2 with 1 added to it. Therefore, suppose x = 2k + 1 and y = 2p + 1 then xy = (2k + 1)(2p + 1) = 4kp + 2k + 2p + 1 = 2(kp + k + p) + 1. Let kp + k + p = q, then we have 2q + 1 which is also odd.
(c) Given that x is odd we want to prove that 3x is also odd. Firstly, we've proven above that xy is odd if x and y are odd. 3 is an odd number and we are told that x is odd. Therefore it follows from the second proof that 3x is also odd.
Answer:
-7
Step-by-step explanation:
-1-6 is like 1+6 but with a negative sign before it.
Total points scored=72(2)+9
=153
Mean=153/7
=21 6/7
=21.9 (3s.f.)