S Purkayastha Solutions for Chapter: The Triangle and its Properties, Exercise 7: Mental Maths

Is it possible to have one angle of an isosceles triangle as an obtuse angle?

One side of a right-angled triangle is $9 \mathrm{cm}$ long and the other side is $6 \mathrm{cm}$. What will be the length of the third side $?$

Two sides of right-angled triangle are $5 \mathrm{cm}$ and $3 \mathrm{cm}$ and find the third side of the right-angled triangle.

Two sides of right-angled triangle are $17 \mathrm{cm}$ and $15 \mathrm{cm}$ and find the third side of the right-angled triangle.

Two sides of right-angled triangle are $6 \mathrm{cm}$ and $10 \mathrm{cm}$ and find the third side of the right-angled triangle.

Two sides of right-angled triangle are $12 \mathrm{cm}$ and $13 \mathrm{cm}$ and find the third side of the right-angled triangle.

Can a triangle have three angles less than $60°$ $?$

Can a triangle have all angles greater than $60°$ $?$