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