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## Question

primary 6 | Maths
| Geometry

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△QRT is isosceles.

QR also = SR (both are sides of a square)

So TR = SR

△ SRT is also isosceles

Use the properties of an isosceles triangle to solve

### See 1 Answer

Angle TRS cannot be 40° as the sum of angle TRS and angle QRT (which gives QRS) would then be 80°, but QRS is actually a right angle (90°), which is a contradiction.

angle TRS = angle QRS - angle QRT

= 90° - 40°

= 50°

Angle RST = (180° - 50°)/2 = 65°