ANSWER
C) Triangle
EXPLANATION
Solving a triangle is the process of calculating unknown side lengths or angle measures of a triangle if certain of the side lengths and/or angle measures are known.
We use the sine rule and cosine rule to find the missing sides and angles.
If the triangle has a right angle, then this is a special case, where we can use the trigonometric ratios and the Pythagoras theorem to find the unknown angles and sides.
No solution
Ex:
Simply 2.40+1.8 to 4.2
N> 75 should be the best one