I don't know how to do this:

Question

Mark Y inside regular pentagon P QRST , so that P QY is equilateral. Is RY T straight? Explain.

Answer 1

the point Y is not on line RT

angle YQR must be 48 degrees (108-60)

if Y on RT then angle YRQ must 72 degrees (108-36)

triangle QYR is formed and angle QYR must be 60 degrees;.

But if Y lies on RT then triangle QRY is isosceles QY=QR=1

and angle QYR must equal angle YRQ

since 60 not equal to 72

Y cannot be on RT

Answer 2