Question 98610
2 COMPLEMENTARY ANGLES ADD UP TO 90 DEGREES.
THEREFORE:
X+(21+2X)=90
X+21+2X=90
3X=90-21
3X=69
X=69/3
X=23 ANSWER.
90-23=67 ANSWER
PROOF
23+21+2*23=90
23+21+46=90
90=90