1 <span>2/9</span>+3 <span>1/3</span>=<span>1 · 9 + 2/9</span>+<span>3 · 3 + 1/3</span>=<span>11/9</span>+<span>10/3</span>=<span>1 · 111 · 9</span>+<span>3 · 103 · 3</span>=<span>119</span>+<span>309</span>=<span>11 + 309</span>=<span>419</span>=4 <span>5/9<span>
</span></span>
1/2=(1*5)/(2×5)=5/10=0.5
1/4=(1×25)/(4×25)=25/100=0.25
1/5=(1×2)/(5×2)=2/10=0.2
1/8=(1×125)/(125×8)=125/1000=0.125
B=4*2=8 P=8*2+4*2= 24 cм. s= 8*4=32см2