<span>this is how i did it
10(9)(d)= 210
90d= 210
d=2.3 feet.</span>
The answer is 9x^8
Hope it helped!!
ANSWER:
d = 15
The swimmer swam 48 kilometres in 15 days.
STEP-BY-STEP EXPLANATION:
Let d = total no. of days the swimmer swam
Total no. of kilometres swam = 48
Average no. of kilometres swam daily = 3.2
THEREFORE:
3.2d = 48
d = 48 / 3.2
d = 15
<h2>
Answer and Explanation to questions 13,14,15</h2>
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, 
<h2>
Answer and Explanation to questions 16,17,18</h2>
∠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)