Figure 1 = 1 triangle = 3 matchsticks  Figure 2 = (1+2) triangle = 3 x 3 = 9 matchsticss.  Figure 3 = (1+2+3) triangle = 6 x 3 = 18 matchsticks.  Figure 4 =  Figure 5 = (1+2+3+4+5) triangle = 15 x 3 = 45 matchsticks. 
SASMO 2015 P2 Q7  Study the figures made with matchsticks below. How many matchsticks are needed to make figure 5? 

$$30$$ 
$$33$$ 
$$39$$ 
$$45$$ 
$$51$$ 