Complete the statements to determine the amount of BTUs needed to properly cool Arthur's apartment.
1 answer:
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Answer:
BD = <u>1</u> unit
AD = <u>1</u> unit
AB = <u>1.6</u> units
AC = <u>1.6</u> units
Step-by-step explanation:
In the picture attached, the triangle ABC is shown.
Given that triangle ABC is isosceles, then ∠B = ∠C
∠A + ∠B + ∠C = 180°
36° + 2∠B = 180°
∠B = (180° - 36°)/2
∠B = ∠C = 72°
From Law of Sines:
sin(∠A)/BC = sin(∠B)/AC = sin(∠C)/AB
(Remember that BC is 1 unit long)
AB = AC = sin(72°)/sin(36°) = 1.6
In triangle ABD, ∠B = 72°/2 = 36°, then:
∠A + ∠B + ∠D = 180°
36° + 36° + ∠D = 180°
∠D = 180° - 36° - 36° = 108°
From Law of Sines:
sin(∠A)/BD = sin(∠B)/AD = sin(∠D)/AB
(now ∠A = ∠B)
BD = AD = sin(∠A)*AB/sin(∠D)
BD = AD = sin(36°)*1.6/sin(108°) = 1
By using the properties of parallel lines, it can be inferred that -
Corrosponding angle goes in the place of first question mark and substitution property of equality goes in the place of second question mark.
What are parallel lines?
Two lines are said to be parallel if on extending them indefinitely, they will never intersect
Transversal is a line that intersects two or more parallel lines
For the first question mark
[Corrosponding angle]
For the second question mark
[Substitution property of equality]
To learn more about parallel lines, refer to the link-
#SPJ1
You want to end up with . Expand this using the angle sum identity for sine:
We want this to line up with . Right away, we know
.
We also need to have
Recall that for all
; this means
Then
So we end up with