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}