Question

(68. Aflați aria pătratului cu diagonalele egale cu 4 cm.
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Answer 1

d = 4 = l√2 => l = 4/√2 = 4√2/2 = 2√2 cm

A = l² = (2√2)² = 4×2 = 8 cm²

Answer 2

${l}^{2} + {l}^{2} = {d}^{2} \\ \\ {4}^{2} = {2l}^{2} \\ \\ 16 = {2l}^{2} \\ \\ {l}^{2} = \frac{16}{2} = 8 \\ \\ l = \sqrt{8} = 2 \sqrt{2} \\ \\ a = l \times l = 2 \sqrt{2} \times 2 \sqrt{2} = 8 {cm}^{2}$