Q17 of 168 Page 4

Calculate the height of an equilateral triangle each of whose sides measures 12 cm.

ABC is an equilateral triangle with side 12cm

AE⊥BC

In ABD andACD

∠ADB=∠ADC=90

AB=AC=12cm

AD=AD (COMMON)

ABDACD

AD²+BD²=AB²

AD²+6²=12²

AD²+36=144

AD²=144-36

AD²=108

AD=

AD=10.39 cm

Each side of a rhombus is 10 cm. If one of its diagonals is 16 cm find the length of the other diagonal.

In an acute-angled triangle, express a median in terms of its sides.

In right-angled triangle ABC in which, if D is the mid-point of BC, prove that .

In Fig. 4.220, D is the mid-point of side BC and . If BC = a, AC = b, AB = c, ED = x, AD = p and AE = h, prove that:

(i) (ii)

(iii)