He can because you can add it mentally. You can just have 23 in your head and count by adding 10 "4" times. 
Hope this helped☺☺
        
                    
             
        
        
        
Answer:
Quadrant 4
Step-by-step explanation:
Csc = 1/sin 
Cos is positive in quadrants 1 and 4
Sin is negative in quadrants 3 and 4
 
        
             
        
        
        
Hack
for y=ax^2+bx+c
the xvalue of the vertex is -b/2a
and the y value is found by subsituting that for x
so
-b/2a
h(t)=2x^2+4x+7
a=2
b=4
-b/2a=-4/(2*2)=-4/4=-1
the y value
h(-1)=2(-1)^2+4(-1)+7
h(-1)=2(1)-4+7
h(1)=2+3
h(1)=5
(-1,5) is da vertex
        
             
        
        
        
A circle equation is :
( x - p )² + ( y - q )² = r², where p and q are coordinates of the center.
The position of the source is : ( - 6, - 4 ) and the range :
r² = 36   ⇒   r = 6
        
                    
             
        
        
        
Answer:
acute and equilateral
Step-by-step explanation:
because all the angles are given equal