Question

Find the perimeter of a rectangle whose length is 6 cm and a diagnol is 6.5 cm

Answer 1

$diagonal \: means \: hypotenuse \\ (hypo) { }^{2} = ( {side \: 1)}^{2} + ( {side2)}^{2} \\ ( {6.5)}^{2} = ( {6)}^{2} + (side 2) {}^{2} \\ 42.25 = 36 + ( {side2)}^{2} \\ 42.25 - 36 = ( {side2)}^{2} \\ 6.25 = ( {side2)}^{2} \\ 2.5 = (side2) \\ perimeter \: of \: rectangle \: = 2(6 + 2.5) \\ = 2(8.5) \\ = 17cm$