Roshel has a square piece of paper DEFG of side 70 m. She cut along the dotted lines shown in Figure 1 to get one small square of area 100 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
= 70 x 70
= 4900 m
2 Area of 8 triangles
= 4900 - 100
= 4800 m
2Area of 4 outer triangles
= 4800 ÷ 2
= 2400 m
2 Area of the inner dotted-line square
= 4900 - 2400
= 2500 m
2 Length of inner dotted-line square
= √2500
= 50 m
Length of HK = 50 m
Answer(s): 50 m