Answer:
n = 24
Step-by-step explanation:
(n + 18) and 2n are "complementary angles:" they add up to 90°.
Thus, n + 18 + 2n = 90. Combining the n terms results in 3n + 18 = 90.
Then 3n = 72. Dividing both sides by 3 results in n = 24.
n is 24, so n + 18 is 42 and 2n is 48. Note that 42 and 48 add up to 90.
