Question

find the value of the variable.
4.
(2r + 3)°
89°

Explanation:

Step1: Note angle - relationship

The two angles are complementary (sum to 90°). So, $(2r + 3)+89=90$.

Step2: Simplify the equation

$2r+3 + 89=90$ simplifies to $2r+92 = 90$.

Step3: Isolate the term with the variable

Subtract 92 from both sides: $2r=90 - 92$, so $2r=-2$.

Step4: Solve for r

Divide both sides by 2: $r=\frac{-2}{2}=-1$.

Answer:

$r = - 1$