Question 25

In ΔDEF measure of angle E is 90°. If secD = 25/7, and DE = 1.4cm, then what is the length (in cm) of side DF?

Solution

Given : DE = 1.4 cm and sec D = $$\frac{25}{7}$$

To find : DF = ?

Solution : In right $$\triangle$$ DEF,

=> $$sec(D)=\frac{DF}{DE}$$

=> $$\frac{25}{7}=\frac{DF}{1.4}$$

=> $$DF=\frac{25}{7}\times1.4=5$$ cm

=> Ans - (A)

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