JAMB - Mathematics (1994 - No. 45)
In the diagram. Find h
\(\frac{12}{7}\)cm
\(\frac{12}{7} \sqrt{6}\)cm
\(\frac{7}{12}\)cm
\(\frac{1}{2}\)cm
Penjelasan
A\(\bigtriangleup\) = \(\sqrt{S(S - a) (S - b)(S - c)}\) (Hero's Formula)
S = \(\frac{a + b + c}{2}\) = \(\frac{5 + 6 + 7}{2}\)
\(\frac{18}{2} = 9\)
A\(\bigtriangleup\) = \(\sqrt{9 \times 4 \times 3 \times 2}\)
\(\sqrt{216} = 6 \sqrt{6}cm^3\)
A\(\bigtriangleup\) = \(\frac{1}{2} \times 6 \times h\)
6\(\sqrt{6} = \frac{1}{2} \times 7 \times h\)
h = \(\frac{12}{7} \sqrt{6}\)cm
S = \(\frac{a + b + c}{2}\) = \(\frac{5 + 6 + 7}{2}\)
\(\frac{18}{2} = 9\)
A\(\bigtriangleup\) = \(\sqrt{9 \times 4 \times 3 \times 2}\)
\(\sqrt{216} = 6 \sqrt{6}cm^3\)
A\(\bigtriangleup\) = \(\frac{1}{2} \times 6 \times h\)
6\(\sqrt{6} = \frac{1}{2} \times 7 \times h\)
h = \(\frac{12}{7} \sqrt{6}\)cm