Answer:
First: 15
Second: 21
Third: 45
Step-by-step explanation:
In order to create the equation we need to represent the evenings with an alebraic term, in thsi case we are going to represent the second evening with an X
Second evening:x
The first night she got 6 fewer calls than the second: Second-6=x-6
The third night she received 3 times the first: 3(first night)=3(x-6)
The equation is First Night plus second night plus third night equals 81.

So the first evening he received 15 calls, the second he received 21 and the third one he received 45.
Answer:
No DB is not a perpendicular bisector of AC
Step-by-step explanation:
This is because as AC is a straight line it's angle degree is 180 which when bisected by DB becomes,
180 ÷ 2 = 90
On both the angles i.e <BDC = <NDA = 90°
To make it a perpendicular bisector but
<BDC is not equal to <NDA is not equal to 90°.
Hence, DB is not a perpendicular bisector of line AC.
<em> </em><em>Sum </em><em>of </em><em>both </em><em>the </em><em>angle </em><em>will </em><em> </em><em>1</em><em>8</em><em>0</em><em> </em><em>because</em><em> of</em><em> </em><em>linear </em><em>pair</em>
now, <em>1</em><em>0</em><em>x</em><em> </em><em>-</em><em> </em><em>2</em><em>0</em><em> </em><em>+</em><em> </em><em>6</em><em>x</em><em> </em><em>+</em><em> </em><em>8</em><em> </em><em> </em><em>=</em><em>. </em><em>1</em><em>8</em><em>0</em><em> </em>
<em> </em><em> </em><em>1</em><em>6</em><em>x</em><em> </em><em>-</em><em> </em><em>1</em><em>2</em><em> </em><em>=</em><em> </em><em>1</em><em>8</em><em>0</em>
<em>1</em><em>6</em><em>x</em><em> </em><em>=</em><em> </em><em>1</em><em>9</em><em>2</em><em> </em>
<em>x=</em><em> </em><em>1</em><em>9</em><em>2</em><em>/</em><em>1</em><em>6</em>
<em>x </em><em>=</em><em> </em><em>1</em><em>2</em>
<em>1</em><em>s</em><em>t</em><em> </em><em>angle </em><em>=</em><em> </em><em>1</em><em>0</em><em>0</em>
<em>2</em><em>n</em><em>d</em><em> </em><em>is </em><em>=</em><em> </em><em>8</em><em>0</em>
<em>Hope</em><em> it</em><em> helps</em><em> and</em><em> your</em><em> day</em><em> will</em><em> full</em><em> of</em><em> happiness</em>
Answer:
the largest angle of the field is 149⁰
Step-by-step explanation:
Given;
perimeter of the triangular filed, P = 120 m
length of two known sides, a and b = 21 m and 40 m respectively
The length of the third side is calculated as follows;
a + b + c = P
21 m + 40 m + c = 120 m
61 m + c = 120 m
c = 120 m - 61 m
c = 59 m
B
↓ ↓
↓ ↓
↓ ↓
A → → → → → → → → → → → C
Consider ABC as the triangular field;
Angle A is calculated by applying cosine rule;

Angle B is calculated as follows;

Angle C is calculated as follows;

Therefore, the largest angle of the field is 149⁰.