I am a little confused about the question you are trying to ask. It is an isosceles triangle because it has two sides of equal length.
The other angle would be...
180-2(55)=70 degrees
Given :
Service cost , c = $40.
Amount paid for each message , m = $0.02 .
To Find :
Equation represents the total cost C in dollars for a month when eric send t text message.
Solution :
Let , total cost be C .
It is an linear equation with slope equal to 0.02 and y-intercept equal to 40.
So ,

Hence, this is the required solution.
Answer:
(a) 8.15
(b) 12.92
Step-by-step explanation:
Given: P = $3000, r = 0.085

Where
A is the Amount
P is the Principal
r is the rate
t is the time
(a) For the amount to double, A = 2 × P
A = 2 × $3000
A = $6000



Take
of both sides

But 
∴ 


t = 8.15
(b) For the amount to double, A = 3 × P
A = 3 × $3000
A = $9000



Take
of both sides

But 
∴ 


t = 12.92
An 544.5
Step-by-step explanation: