Pythagoras’ theorem

The Maths Habit Handout to print

A TV is sold as 55 inches.
Which length is 55 inches?

Corner to corner

Hypotenuse: The longest side of a right-angled triangle. It is opposite the right angle.

Label the hypotenuse of each triangle c.

a² + b² = c²

c is the hypotenuse

c² =15² + 20²c² =225 + 400c² =625c =√625 = 25 cm

c² =21² + 20²c² =441 + 400c² =841c =√841 = 29 cm

c² =15² + 20²c² =225 + 400c² =625c =√625 = 25 cm

Give your answer to 1 decimal place.

c² =9² + 14²c² =81 + 196c² =277c =√277 = 16.643…= 16.6 cm

c² =15² + 20²c² =225 + 400c² =625c =√625 = 25 cm

Give your answer to 1 decimal place.

c² =12² + 7²c² =144 + 49c² =193c =√193 = 13.892…= 13.9 cm

c² =15² + 20²c² =225 + 400c² =625c =√625 = 25 cm

c² =8² + 15²c² =64 + 225c² =289c =√289 = 17 cm

c² =15² + 20²c² =225 + 400c² =625c =√625 = 25 cm

Give your answer to 1 decimal place.

c² =3.2² + 4.5²c² =10.24 + 20.25c² =30.49c =√30.49 = 5.521…= 5.5 m

A field is a rectangle 90 m by 120 m. Sam walks along two sides to reach the opposite corner. Mia walks straight across. How much further does Sam walk?
60 m
A TV screen is 48 inches wide and 27 inches tall. What size is it sold as?
55 inches
A builder checks a corner of a room. She marks 60 cm along one wall and 80 cm along the other. The marks are 1.05 m apart. Is the corner a right angle? Show how you know.
No (100 cm)

Answer sheet

Find the length x.
x = 15 cm
Find the length of the diagonal of the rectangle to 1 decimal place.
8.1 cm
A triangle has sides of 8 cm, 11 cm and 14 cm. Is it right angled? Show how you know.
No: 64 + 121 = 185, not 196