Look at triangle MNO
Which statements about the lengths of the sides of the triangle is true?
A. The length of side MN is equal to the sum of the lengths of sides MO and ON
B. The length of side MN is double of the sum of the lengths of sides MO and ON
C. The length of side MN is less than the sum of the lengths of sides MO and ON
D. The length of side MN is three times the sum of the lengths of sides MO and ON

Question

Look at triangle MNO
 Which statements about the lengths of the sides of the triangle is true?
A.  The length of side MN is equal to the sum of the lengths of sides MO and ON
B.  The length of side MN is double of the sum of the lengths of sides MO and ON
C.  The length of side MN is less than the sum of the lengths of sides MO and ON
D.  The length of side MN is three times the sum of the lengths of sides MO and ON

directrix · Answer

This is a direct application of the Triangle Inequality Theorem. (There's no substitute for learning the theorems.)

C.  The length of side MN is less than the sum of the lengths of sides MO and ON