AB = 10 cm. ∴ AF = FB = 5 cm. CD = 24 cm. ∴ CE = DE = 12 cm. Let OE = x cm ∴ OF = (17 – x) cm From D ODE, OD = √OE2+DE2 = √x2+122 ... (i) From Δ OAF OA = √OF2+AF2 = √(17−x)2+52 ... (ii) Since OA = OD ∴ √x2+122 = √(17−x)2+52 ⇒ x2 + 144 = 289 - 34x + x2 + 25 ⇒ 34x = 289 + 25 - 144 = 170 ⇒ x =
170
34
= 5 ∴ From equation (i), OD = √x2+122 = √52+144 = √169 = 13 cm