The ratio of an area of two triangles is 5 : 7 and ratio of height is 7 : 5.  Find the ratio of their base?

25 : 49 15 : 21 49 : 25 20 : 28

25 : 49

Area1 :  Area2 = 5 : 7 ⇒ \(\frac{1}{2}\) b1h1 :  \(\frac{1}{2}\) b2h2  = 5  :  7 ⇒ b1 × 7  :  b2 × 5  =  5 : 7 ⇒ b1  :  b2  =  5 × 5 : 7 × 7 = 25 : 49