bantuin

<ul><li>Panjang AB dapat kita tentukan dengan menggunakan teorema pitagoras: <strong>AB^2 + AD^2 = BD^2</strong>.&nbsp;</li><li>Dalam sebuah persegi, keempat sisinya sama panjang, maka <strong>AB = AD</strong></li></ul><p>&nbsp; &nbsp; &nbsp; &nbsp;Sehingga diperoleh</p><p>&nbsp; &nbsp; &nbsp; &nbsp; &nbsp;<strong>AB^2 + AB^2 = BD^2</strong></p><p>&nbsp; &nbsp; &nbsp; &nbsp; &nbsp;2AB^2 = BD^2</p><p>&nbsp; &nbsp; &nbsp; &nbsp; &nbsp;2AB^2 = (4√5)^2</p><p>&nbsp; &nbsp; &nbsp; &nbsp; &nbsp;2AB^2 = 16 x 5</p><p>&nbsp; &nbsp; &nbsp; &nbsp; &nbsp;Kedua ruas dikalikan dengan 1/2</p><p>&nbsp; &nbsp; &nbsp; &nbsp; &nbsp;2AB^2 x 1/2= 16 x 5 x 1/2</p><p>&nbsp; &nbsp; &nbsp; &nbsp; &nbsp;AB^2 = 40</p><p>&nbsp; &nbsp; &nbsp; &nbsp; &nbsp;AB = √40</p><p>&nbsp; &nbsp; &nbsp; &nbsp; &nbsp;AB = 2√10</p><p>&nbsp; &nbsp; &nbsp; &nbsp; &nbsp;<strong>Jadi panjang AB = 2√10</strong></p><p>&nbsp;</p><ul><li>Keliling ABCD = 4 x 2√10&nbsp;</li></ul><p>&nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; = 8√10</p><p>&nbsp; &nbsp; &nbsp; &nbsp;&nbsp;<strong>Jadi keliling ABCD = 8√10</strong></p>