Class 5 Maths Chapter 3 Important Question Answers - Chapter 3 - How many square

Q1: Find the area of the shaded portion in the following figures.

Ans: Area of shaded portion = area of trapezium ABCH + area of trapezium CDEF

Q2: Find the area

Ans: Area of the given figure= Area of DCF + Area of EDG + Area to trapezium FCBH + Area of EGA + Area of AHB Therefore,
⇒ area of DCF = 1/2 × base × height = 1/2 × 100 × 100 = 10000/2 = 5000 m² 

Q3: Convert the following 50 cm² in MM²
Ans: 1 cm² = 100mm²
50 cm² = 5,000 mm²

Q4: Fill in the blanks:
The area of a closed plane figure is measured in ________
Ans: The area of a closed plane figure is measured in sq. units. 

Q5: Find the area of the field shown along side. All dimension are in metres

Ans: Area of ABCDE = Area of ΔABH+ area of trap BCFH + area of ΔCDF + Area of ΔAED
Now, area of ABH
= × AH × HB
= 1/2 × 25 × 25
= 625/2 m² = 312.5m²
Area of trap BCFH = 1/2 × (HB + FC) = HF
= 1/2 (25 + 50) × 55m²

Area of ΔCDF = × FC × DF
= 1/2 × 50 × 50 m² = 1250 m²
Area of ΔAED = × AD × EG
= 1/2 × 130 × 60
= 3900m²
Thus, area of ABCDE = 312.5m² + 2062.5m² + 1250m² + 3900m²
= 7225m²

Q6: Find the area enclosed by the given figure

Ans: From the fig. it is clear that CDEF is a trapezium and ABCF is a square.
Area of trapezium =
Where a = ED and b = FC
Area of figure ABCDEF = Area of C DEF + Area of square ABCF
= 1/2 × (7 + 18) × 8 + (18 × 18)
= 100 + 324
= 424 cm²

Q7: Diagram of the adjacent picture frame has outer dimensions 28 cm × 24 cm and inner dimensions 20 cm × 16 cm. Find the area of the shaded part of a frame, if the width of each section is the same

Ans: Given: outer dimensions 28 cm × 24 cm and inner dimensions 20 cm × 16 cm
Area of shaded region = (area EF JI - area EFGH) + 2 area ΔAIH
= (20 × 20 - 16 × 20) + 2 × 1/2 × 4 × 4
= (400 - 320) + 16 = 80 + 16 = 96 cm²

Q8: Find the area enclosed by the given figure

Ans: Area of figure ABCDEF = ar. trap ADEF + ar. rec ABCD
= 1/2 (6 + 15) × 8 + 20 × 15
= 84 + 300 = 384 cm²

Q9: Rajni says 1 sq. m = 100² sq. cm. Do you agree? Explain
Ans: Yes it is true that 1 sq m = 100² sq. cm.
It is known that 1 m = 100 cm
Squaring both sides, we get,
(1 m)² = (100 cm)² 
1 m² = 1002 cm² 

Q10: Ravi completed the shape like this. What is the area occupied by the blue triangle?

Ans: Area of blue triangle = 1/2 × 4 × 2 = 2 sq. units.