Donald Cartmill

Stefan borrowed a watch from his friend ,returned home and set his grandfather clock to the correct time

    90 -70= 20 deg using side of square as "a" , we have tan20 = o/a and then O= atan 20 or 0.3639a; The right leg of the  triangle and  the top portion of the right side               20 +45 =65 ; 90-65  =     25 degrees  the other angle at top left and therefore the 3rd angle is 65;                                 tan 25 = o/a  or  o = a tan25;        o = 0.4663a.   since a  is the length of a side then the bottom leg of the lower right triangle = 1 - 0.4663 = 0.5336a ;          the vertical leg of the lower triangle is 1 -   0.3639a  =     0.6360a.  we will designate the left angle of the bottom triangle as Y ,  So we can say Tan Y = o/a or 0.6360a / 0.5336a;      tan Y = 1.1917;  Y = 50    Adding the bottom angles we have 65 + 50 = 115 :   180 - 115 =65 degrees              X = 65 degrees