Answer: The required number of books that Ruben had before purchases is 50.
Step-by-step explanation: Given that Ruben bought 6 new books for his collection that increased his collection by 12%.
We are to find the number of books that Ruben had before purchases.
Let x denotes the number of books that Ruben had before purchases.
Then, according to the given information, we have
Thus, the required number of books that Ruben had before purchases is 50.
13) as given in the question.
14) Since Y is the midpoint of XZ. So, Y will divide XZ in equal halves into XY and YZ.
15)
and
. So,
∠3 is supplementary to ∠1 means: ∠3 + ∠1 = 180°
And, according to figure ∠1 + ∠2 = 180° as ∠1 and ∠2 form a straight line.
∠3 + ∠1 = 180° .............(i)
∠1 + ∠2 = 180° .............(ii)
subtracting equation (i) and (ii) will give ∠3 = ∠2 ..........(iii)
15) ∠3 is supplementary to ∠1 as given in the question
16) ∠2 is supplementary to ∠1 as shown be equation (ii)
18) ∠3 ≅ ∠2 as shown by equation (iii)
<h2>Answer and Explanation to questions 19</h2>∠3 and ∠4 form a straight line. Therefore, ∠3 + ∠4 = 180° .......(i)
∠4 and ∠5 form a straight line. Therefore, ∠4 + ∠5 = 180° .......(ii)
subtracting equation (i) and (ii)
∠3 + ∠4 - (∠4 + ∠5) = 180°-(180°)
∠3 + ∠4 - ∠4 - ∠5 = 180°-180°
∠3 - ∠5 = 0
∴ ∠3 = ∠5 (Hence Proved)