To find the relative frequencies, divide each frequency by the total number of throws - in this case, 100.
Red: 10/100=1/10=0.1
Yellow:35/100=0.35
Blue:48/100= 0.48
Misses: 7/100=0.07
The event of landing in the red region has a relative frequency of 0.1 which means the dart landed in the red region about 10% (0.1 x 100%) of the time.