Mixed Problems
1. **Convert 678 cm² to m²**
Since 1 m = 100 cm, area conversion is: $$1 \text{ m}^2 = 100^2 = 10,000 \text{ cm}^2$$
Therefore, $$678 \text{ cm}^2 = \frac{678}{10,000} = 0.0678 \text{ m}^2$$
2. **Convert 0.58 m² to cm²**
Using the same factor: $$0.58 \text{ m}^2 = 0.58 \times 10,000 = 5800 \text{ cm}^2$$
3. **Solve equation: $$5(7q - 3) = 28(q - 1)$$**
Step 1: Expand both sides:
$$35q - 15 = 28q - 28$$
Step 2: Bring variables to one side and constants to the other:
$$35q - 28q = -28 + 15$$
$$7q = -13$$
Step 3: Solve for $$q$$:
$$q = \frac{-13}{7}$$
4. **Sum of four consecutive even numbers is 76. Find the smallest number.**
Let the smallest even number be $$x$$.
The numbers are: $$x, x+2, x+4, x+6$$
Their sum is:
$$x + (x+2) + (x+4) + (x+6) = 76$$
Simplify:
$$4x + 12 = 76$$
$$4x = 76 - 12 = 64$$
$$x = \frac{64}{4} = 16$$
So smallest even number is $$16$$.
5. **Area of the given shape (rectangle with four quarter circles removed).**
Step 1: Calculate area of rectangle:
$$6 \text{ m} \times 2 \text{ m} = 12 \text{ m}^2$$
Step 2: Each quadrant is a quarter circle with radius $$1$$ m.
Area of one circle:
$$\pi r^2 = \pi \times 1^2 = \pi$$
Area of one quadrant:
$$\frac{\pi}{4}$$
Four quadrants make one full circle:
$$4 \times \frac{\pi}{4} = \pi$$
Step 3: Area of the shape after removing four quadrants:
$$12 - \pi \approx 12 - 3.1416 = 8.8584 \text{ m}^2$$
6. **Find value of:**
$$\frac{-8 - \{18 + (-4)^2\} + 2^3}{2}$$
Step 1: Calculate inside the braces:
$$(-4)^2 = 16$$
So,
$$18 + 16 = 34$$
Step 2: Calculate $$2^3 = 8$$
Step 3: Substitute back:
$$\frac{-8 - 34 + 8}{2} = \frac{-34}{2} = -17$$
7. **Solve equation:**
$$\frac{6(x-2)}{7} = \frac{2(x-7)}{3}$$
Step 1: Cross multiply:
$$3 \times 6(x-2) = 7 \times 2(x-7)$$
$$18(x-2) = 14(x-7)$$
Step 2: Expand:
$$18x - 36 = 14x - 98$$
Step 3: Bring terms together:
$$18x - 14x = -98 + 36$$
$$4x = -62$$
Step 4: Solve for $$x$$:
$$x = \frac{-62}{4} = -15.5$$