Question

if the distance between the points A (k,0) and B (0,k) is 10, find the possible values of k.

Answer 1

hello..........

by distance formula 
√[k-0]²+[0-k]²=AB
√k²+k²=10
√2k²=10
  k√2=10
  k=10/√2
k=5√2
k=5×1.414              [using√2=1.414]
k=+-7.07

Answer 2

by distance formula
distance between AB = [(x2 - x1)^2 + (y2 - y1)^2] ^1/2
                               10= [(0 - k)^2 + (k - 0)^2] ^1/2
                               10= [(0 - 2.0.k + k^2) + (k^2 - 2.0.k + 0)] ^1/2
                               10= (k^2 +k^2) ^1/2
                               10= (2k^2) ^1/2
                               10=  k(2^1/2)
therefore                 k= 10/2^1/2