fill in the blanks.
1. the surface area of a cylinder of a base radius r and height is h. ( ) .
2. if base area of a cube is 180 CM and it's volume is 900 CM ( cube) then the height of a cuboid is ( ) .
3. three cubes of a metal whose edges are 6 CM, 8 CM, and 10 CM respectively are melted to form a single cube. the edge of the new cube is ( ).
4. the length of the diagonal of a cuboid with length 2 CM and breath 4 CM height 4 CM is ( ).
Answers
Step-by-step explanation:
Volume of a cylinder = πr2 hπr2 h
Lateral surface=2πrh=2πrh
Total surface area =2πr(h+r)=2πr(h+r)
(i) Base radius = 7 cm; height = 50 cm
Now, we have the following:
Volume=227×7×7×50=7700 cm3=227×7×7×50=7700 cm3
Lateral surface area=2πrh=2πrh=2×227×7×50=2200 cm2=2×227×7×50=2200 cm2
Total surface area =2πr(h+r)=2πr(h+r)=2×227×7(50+7)=2508 cm2=2×227×750+7=2508 cm2
(ii) Base radius = 5.6 m; height = 1.25 m
Now, we have the following:
Volume=227×5.6×5.6×1.25=123.2 m3=227×5.6×5.6×1.25=123.2 m3
Lateral surface area=2πrh=2πrh=2×227×5.6×1.25=44 m2=2×227×5.6×1.25=44 m2
Total surface area =2πr(h+r)=2πr(h+r)=2×227×5.6(1.25+5.6)=241.12 m2=2×227×5.61.25+5.6=241.12 m2
(iii) Base radius = 14 dm = 1.4 m, height = 15 m
Now, we have the following:
Volume=227×1.4×1.4×15=92.4 m3=227×1.4×1.4×15=92.4 m3
Lateral surface area=2πrh=2πrh=2×227×1.4×15=132 m2=2×227×1.4×15=132 m2
Total surface area =2πr(h+r)=2πr(h+r)=2×227×1.4(15+1.4)=144.32 cm2