Problem:
Point B is due east of point A. Point C is due north of point B. The distance between points A and C is 102β meters, and β BAC=45β. Point D is 20 meters due north of point C. The distance AD is between which two integers?
Answer Choices:
A. 30 and 31
B. 31 and 32
C. 32 and 33
D. 33 and 34
E. 34 and 35
Solution:
Note that β ABC=90β, so β³ABC is a 45β45β90β triangle. Because hypotenuse AC=102β, the legs of β³ABC have length 10. Therefore AB=10 and BD=BC+CD=10+20=30. By the Pythagorean Theorem,
AD=102+302β=1000β
Because 312=961 and 322=1024, it follows that (B)31<AD<32β.