Question

find the measure of an angle 15less than four times its complement

Answer 1

Such questions must be solve using a variable so that we may consider that variable to be a standard and other values of the question may be related to it.

Let the required angle be ' x ' °.

Hence we know that sum of two complementary angles is 90°.

And, The complement of x = ( 4x - 15 )°

So,

x + ( 4x - 15 ) = 90
x + 4x - 15 = 90
5x = 90 + 15
5x = 105
x = 105 / 5
x = 21 °

Hence,

The required angle = x ° = 21 °

Answer 2

let the angle be X then its complement be also x
so4,x+x-15=90
5x-15=90
5x=90+15
5x=105
x=105/5
x=21