For #4, for any right triangle a^2 + b^2 should equal c^2. Square roots are just numbers to a power of 1/2. You can multiply the exponents together of #^(2 * 1/2) and simply get #. With that in mind, we can use sqrt2 as our a, sqrt3 as b, and sqrt5 as c, since c is always the largest number. For A, sqrt2 squared is 2, for B, sqrt3 squared is 3, and c is 5. Since 2+3 does indeed equal 5 you have a right triangle.
For #5, dilating by 3 means our length will be three times as long as whatever it is there. To find out how long the line is, we can make a right triangle. The differences between the x values are 6, and the differences between the y values are 12. A^2 + b^2 = c^2, 144 + 36 = 180, c= sqrt180, which is approx. 13.416. Multiply that by 3 and you get ≈40.25 as K’L’.
