Farsaingeachd ceithir-cheàrnaich

Gus farsaingeachd ceithir-cheàrnaich obrachadh a-mach, feumaidh fios a bhith againn air dà fhoirmle bunaiteach.

\(\text{Farsaingeachd ceart-cheàrnaich = faid \times leud}\) (\(A = l \times b\))

\(\text{Farsaingeachd triantain} = \frac{1}{2} \times \text{bonn} \times \text{àirde}\) (\(A = \frac{1}{2}bh\))

Question

Obraich a-mach farsaingeachd a' cheart-cheàrnaich gu h-ìosal.

Diagram of a 7cm x 5cm rectangle

\[A = l \times b\]

\[= 7 \times 5\]

\[= 35\,c{m^2}\]

Question

Obraich a-mach farsaingeachd an triantain gu h-ìosal.

Diagram of a 6cm x 8cm right-angled triangle

\[A = \frac{1}{2}bh\]

\[= \frac{1}{2} \times 8 \times 6\]

\[= \frac{1}{2} \times 48\]

\[= 24\,c{m^2}\]