Answer:
r= 1.69
Step-by-step explanation:
The question is an illustration of permutation and combinations.
- The number of ways she can choose 4 out of the 7 paintings is 35
- The number of ways she can arrange 4 out of the 7 paintings is 840
The given parameters are:


<u>(a) Choose 4 of 7 paintings</u>
Choosing 4 of 7 paintings implies combination.
So, we have:

Substitute values for n and r


Expand


Hence, the number of ways she can choose 4 out of the 7 paintings is 35
<u>(b) Arrange 4 of 7 paintings</u>
Arranging 4 of 7 paintings implies permutation.
So, we have:

Substitute values for n and r


Expand


Hence, the number of ways she can arrange 4 out of the 7 paintings is 840
Read more about permutation and combinations at:
brainly.com/question/15301090
Step-by-step explanation:
<em>Triangles and the Pythagorean Theorem</em>
- The Pythagorean Theorem, a2+b2=c2, a 2 + b 2 = c 2, can be used to find the length of any side of a right triangle.
- The side opposite the right angle is called the hypotenuse (side c in the figure).
<em>(note: Pythagorean means hypotenuse)</em>
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<em>hope this helps </em>
To prove:

Solution:

Multiply first term by
and second term by
.

Using the identity: 

Denominators are same, you can subtract the fractions.

Using the identity: 

Using the identity: 

------------ (1)

Using the identity: 


------------ (2)
Equation (1) = Equation (2)
LHS = RHS

Hence proved.
Examples of metals: copper, iron, tin,
Examples of nonmetals: hydrogen, helium, nitrogen,