1. In ΔDEF measure of angle E is $$90^\circ$$. If $$cos D = \frac{5}{13}$$, and DE = 1cm, then what is the length (in cm) of side EF?
Write Comment
Comments
By: anil on 05 May 2019 03.00 pm
Given : DE = 1 cm and cos D = $$frac{5}{13}$$ To find : EF = ? Solution : In right $$ riangle$$ DEF, => $$cos(D)=frac{DE}{DF}$$ => $$frac{5}{13}=frac{1}{DF}$$ => $$DF=frac{13}{5} imes1=2.6$$ cm $$ herefore$$ $$(DF)^2=(DE)^2+(EF)^2$$ => $$(EF)^2=(2.6)^2-(1)^2$$ => $$(EF)^2=6.76-1=5.76$$ => $$EF=sqrt{5.76}=2.4$$ cm => Ans - (B)
Terms And Service:We do not guarantee the accuracy of available data ..We Provide Information On Public Data.. Please consult an expert before using this data for commercial or personal use