Question:
Mrs Tan decorated opposite sides of a rectangular room for her son’s birthday party. On one side, she hung triangular flags of base 15 cm from one end to the other without leaving any gaps as shown in Figure 1.
On the other side, she hung photographs of her son from strings tied 9 cm apart, the first photo and the last photo 9 cm away from the wall as shown in Figure 2.
She used 19 more photos than flags. What was the length of the room in metres?