ABC and DEF are similar isoceles triangles. AB=BC=5cm, AC=6cm, DF=12cm. What is the area of DEF?

We first split ABC into two right-angled triangles. We name the midpoint of AC, M. AM=1cm, and BM=sqrt(52-32)=4 by Pythagoras. The area of ABC =1/2ACBM=1/264=12. We can see that the side lengths of DEF are greater than the side lengths of ABC by a factor of two. The area is therefore greater than ABC by a factor of 22=4. So the area of DEF=4*12=48

PG
Answered by Peter G. Maths tutor

3236 Views

See similar Maths GCSE tutors

Related Maths GCSE answers

All answers ▸

ln(2x^2 +9x-5) =1+ ln( x^2+2x-15)


How do I solve 7x – 8 = -3x + 2?


In a triangle ABC, side BC = 8.1 cm, side AC = 7 cm, and angle ACB = 30 degrees. What is the area of the triangle?


How many people chose A?


We're here to help

contact us iconContact ustelephone icon+44 (0) 203 773 6020
Facebook logoInstagram logoLinkedIn logo

© MyTutorWeb Ltd 2013–2025

Terms & Conditions|Privacy Policy
Cookie Preferences