9) An isosceles right triangle has sides in the ratio 1 : 1 : √2. That is, the legs have length 1/√2 times the length of the hypotenuse. To get the value of x, you apply that multiplier 4 times to the hypotenuse length 4.
... x = (1/√2)⁴ × 4 = 1/4 × 4
... x = 1
10) The hypotenuse of a 30-60-90 right triangle is double the length of the shortest side, so the shortest hypotenuse has length 2. Each successive hypotenuse is 2/√3 times the length of the long side (the next shorter hypotenuse). Then x is ...
... x = (2/√3)⁴ × 2 = 2⁵/3²
... x = 32/9
