Answer: 18
Step-by-step explanation:
this is because complementary angles add up to 90 degrees so you would just subtract 72 from 90 to get your answer :)
y = -
x + 
the equation of a line in slope- intercept form is
y = mx + c ( m is the slope and c the y-intercept )
y = 4x + 5 is in this form with slope m - 4
Given the slope of a line m, then the slope (
) of a line perpendicular to it is
= - (1 / m ) = - 
y = -
x + c is the partial equation of the perpendicular line
to find c, substitute ( 2, 7 ) into the partial equation
7 = -
+ c ⇒ c = 
y = -
x +
← equation of perp. line
V (cube)=9³=729 cm³
V (cone)=1/3*π*R²*H= 1/3*π*3²*9=84.8 cm³
V (metal)= 729-84.8=644.2 cm³