Question

Triangle QRP right angled at Q, QR=18cm. Altitude is drawn from Q to RP to form triangle QRS where RS=9cm and triangle QPS where PS=27cm. Angle Q is labelled theta.

Observe the figure. Which of these is the value of cos theta?

Answer 1

Answer:

first we have to find QS

whe an use phythagoras theoram in first part of the figure

√(18^2-9^2)

which is √243

now in the second part of triangle we have to find QP

again using phythagoras theoram

whe get

√(243+27^2)

√972

now cos theta = base/hypotenuse

which equals

√243/√972

or √243/972

√0.25

or 1/√4

or 1/2

or 0.5