In the figure given below, CD = 30 cm and EF = 24 cm. Find the length of AB (in cm).
Explanation:
CP = PD = 30/2 = 15 cm
EP = PF = 24/2 = 12 cm
∴ CE = FD = 15 – 12 = 3 cm
In ∆OPC, R2 = OP2 + PC2 …(1)
In ∆OPF, r2 = OP2 + PF2 …(2)
(1) - (2)
R2 – r2 = 152 - 122 = 225 – 144 = 81 …(3)
Now, in ∆OAQ
AO2 = AQ2 + OQ2
⇒ AQ2 = AO2 – OQ2
AQ2 = R2 – r2 = 81
⇒ AQ = 9
⇒ AB = 2 × 9 = 18
Hence, option (a).
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