In Fig. 15.87, X and Y are the mid-point of AC and AB respectively, QP||BC and CYQ and BXP are straight lines. Prove that:
ar(Δ ABP) = ar(Δ ACQ).
In a ΔAXP and ΔCXB,
∠PAX = XCB (Alternative angles AP || BC)
AX = CX (Given)
∠AXP = ∠CXB (Vertically opposite angles)
ΔAXP ≅ ΔCXB (By ASA rule)
AP = BC (By c.p.c.t) (i)
Similarly,
QA = BC (ii)
From (i) and (ii), we get
AP = QA
Now,
AP || BC
And,
AP = QA
Area (APB) = Area (
ACQ) (Therefore, Triangles having equal bases and between the same parallels QP and BC)