VIDEO: Canada's Brooke Henderson wins first LPGA major at Sahalee

The 18-year-old shot a 6-under-par 65 - the best round of the tournament - Sunday at Sahalee Country Club in Sammamish. Henderson edged New Zealand's Lydia Ko, the No. 1 golfer in the world, on the first playoff hole to win the KPMG Women's PGA Ch