Abi has a square piece of paper DEFG of side 7 m. She cut along the dotted lines shown in Figure 1 to get one small square of area 1 m
2 and 8 identical right-angled triangles. Triangle HJK in Figure 2 is one such triangle. Find the length of HK.
Area of the square piece of paper
= 7 x 7
= 49 m
2 Area of 8 triangles
= 49 - 1
= 48 m
2Area of 4 outer triangles
= 48 ÷ 2
= 24 m
2 Area of the inner dotted-line square
= 49 - 24
= 25 m
2 Length of inner dotted-line square
= √25
= 5 m
Length of HK = 5 m
Answer(s): 5 m